diff --git a/components/bootloader_support/bootloader_flash/src/bootloader_flash.c b/components/bootloader_support/bootloader_flash/src/bootloader_flash.c
index f1abd50036d..d85ebcec856 100644
--- a/components/bootloader_support/bootloader_flash/src/bootloader_flash.c
+++ b/components/bootloader_support/bootloader_flash/src/bootloader_flash.c
@@ -416,8 +416,8 @@ void bootloader_munmap(const void *mapping)
         mmu_hal_unmap_all();
 #else
         cache_hal_suspend(CACHE_LL_LEVEL_EXT_MEM, CACHE_TYPE_ALL);
-        mmu_hal_unmap_region(0, FLASH_MMAP_VADDR, current_mapped_size);
         cache_hal_invalidate_addr(FLASH_MMAP_VADDR, current_mapped_size);
+        mmu_hal_unmap_region(0, FLASH_MMAP_VADDR, current_mapped_size);
         cache_hal_resume(CACHE_LL_LEVEL_EXT_MEM, CACHE_TYPE_ALL);
 #endif
 #endif
diff --git a/components/esp_tee/CMakeLists.txt b/components/esp_tee/CMakeLists.txt
index dcba631e4d3..33dd106bc34 100644
--- a/components/esp_tee/CMakeLists.txt
+++ b/components/esp_tee/CMakeLists.txt
@@ -9,7 +9,7 @@ idf_build_get_property(target IDF_TARGET)
 # ESP-TEE is currently supported only on the ESP32-C6, H2, C5 and C61 SoCs
 set(SUPPORTED_TARGETS "esp32c6" "esp32h2" "esp32c5" "esp32c61")
 if(NOT target IN_LIST SUPPORTED_TARGETS)
-    message(STATUS "ESP-TEE is currently supported only on the ${SUPPORTED_TARGETS} SoCs")
+    # ESP-TEE Kconfig is gated on the supported targets; nothing to register elsewhere.
     return()
 endif()
 
diff --git a/components/esp_tee/include/private/esp_tee_binary.h b/components/esp_tee/include/private/esp_tee_binary.h
index aca66276090..726e87be2fc 100644
--- a/components/esp_tee/include/private/esp_tee_binary.h
+++ b/components/esp_tee/include/private/esp_tee_binary.h
@@ -57,6 +57,14 @@ extern "C" {
 #error "CONFIG_SECURE_TEE_DROM_SIZE must be a multiple of SOC_MMU_PAGE_SIZE"
 #endif
 
+/* With HAL assertions disabled (level 0), a failed HAL_ASSERT() expands to
+ * __builtin_unreachable(): the compiler then optimizes assuming the asserted
+ * preconditions always hold, turning any unvalidated HAL input into undefined
+ * behavior. The TEE must never be built this way. */
+#if CONFIG_SECURE_ENABLE_TEE && (CONFIG_HAL_DEFAULT_ASSERTION_LEVEL < 1)
+#error "ESP-TEE requires HAL assertions (CONFIG_HAL_DEFAULT_ASSERTION_LEVEL >= 1)"
+#endif
+
 /* TEE Secure Storage partition label and NVS namespace */
 #define ESP_TEE_SEC_STG_PART_LABEL    "secure_storage"
 #define ESP_TEE_SEC_STG_NVS_NAMESPACE "tee_sec_stg_ns"
diff --git a/components/esp_tee/scripts/esp_tee_sec_stg_keygen/README.md b/components/esp_tee/scripts/esp_tee_sec_stg_keygen/README.md
index 3e949fab7b2..9bb50b6a1ff 100644
--- a/components/esp_tee/scripts/esp_tee_sec_stg_keygen/README.md
+++ b/components/esp_tee/scripts/esp_tee_sec_stg_keygen/README.md
@@ -18,6 +18,8 @@ options:
   -o, --output OUTPUT   output binary file name
   -i, --input INPUT     input key file (.pem for ecdsa, .bin for aes)
   --write-once          make key persistent - cannot be modified or deleted once written
+  --tee-only            mark key as owned exclusively by the TEE - the REE cannot use, generate or clear it
+  -h, --help            Show this message and exit
 ```
 
 ### ECDSA Keys
@@ -31,7 +33,7 @@ python esp_tee_sec_stg_keygen.py -k ecdsa_p384 -o ecdsa_p384_k0.bin
 
 ```bash
 openssl ecparam -name prime256v1 -genkey -noout -out ecdsa_p256.pem
-python esp_tee_sec_stg_keygen.py -k ecdsa_p256 -o ecdsa_p256_k1.bin -i ecdsa_p256.pem --write-once
+python esp_tee_sec_stg_keygen.py -k ecdsa_p256 -o ecdsa_p256_k1.bin -i ecdsa_p256.pem --write-once --tee-only
 ```
 
 ### AES-256 Key
diff --git a/components/esp_tee/scripts/esp_tee_sec_stg_keygen/esp_tee_sec_stg_keygen.py b/components/esp_tee/scripts/esp_tee_sec_stg_keygen/esp_tee_sec_stg_keygen.py
index 49b3836a437..87781547572 100644
--- a/components/esp_tee/scripts/esp_tee_sec_stg_keygen/esp_tee_sec_stg_keygen.py
+++ b/components/esp_tee/scripts/esp_tee_sec_stg_keygen/esp_tee_sec_stg_keygen.py
@@ -31,6 +31,7 @@ class KeyType(Enum):
 class Flags(IntFlag):
     NONE = 0x00000000
     WRITE_ONCE = 0x00000001
+    TEE_ONLY = 0x00000002
 
 
 # === Key Generators ===
@@ -112,6 +113,11 @@ def parse_args() -> argparse.Namespace:
         action='store_true',
         help='make key persistent - cannot be modified or deleted once written',
     )
+    parser.add_argument(
+        '--tee-only',
+        action='store_true',
+        help='mark key as owned exclusively by the TEE - the REE cannot use, generate or clear it',
+    )
     return parser.parse_args()
 
 
@@ -122,12 +128,16 @@ def main() -> None:
     flags = Flags.NONE
     if args.write_once:
         flags |= Flags.WRITE_ONCE
+    if args.tee_only:
+        flags |= Flags.TEE_ONLY
 
     print(f'[+] Generating key of type: {key_type.name} (value: {key_type.value})')
     if args.input:
         print(f'[+] Using user-provided key file: {args.input}')
     if args.write_once:
         print('[+] WRITE_ONCE flag is set')
+    if args.tee_only:
+        print('[+] TEE_ONLY flag is set')
 
     key_data = generate_key_data(key_type, flags, args.input)
 
diff --git a/components/esp_tee/subproject/components/attestation/esp_att_utils_crypto.c b/components/esp_tee/subproject/components/attestation/esp_att_utils_crypto.c
index 6ac7557f2ab..7a5bd54f1ec 100644
--- a/components/esp_tee/subproject/components/attestation/esp_att_utils_crypto.c
+++ b/components/esp_tee/subproject/components/attestation/esp_att_utils_crypto.c
@@ -42,6 +42,8 @@ static esp_err_t gen_ecdsa_keypair_secp256r1(esp_att_ecdsa_keypair_t *keypair)
     esp_tee_sec_storage_key_cfg_t key_cfg = {
         .id = (const char *)(ESP_ATT_TK_KEY_ID),
         .type = ESP_SEC_STG_KEY_ECDSA_SECP256R1,
+        /* The attestation key must never be usable from the REE */
+        .flags = SEC_STORAGE_FLAG_TEE_ONLY,
     };
 
     esp_err_t err = esp_tee_sec_storage_gen_key(&key_cfg);
diff --git a/components/esp_tee/subproject/components/tee_sec_storage/include/esp_tee_sec_storage.h b/components/esp_tee/subproject/components/tee_sec_storage/include/esp_tee_sec_storage.h
index 8d863f459b9..61d6ea9a3f3 100644
--- a/components/esp_tee/subproject/components/tee_sec_storage/include/esp_tee_sec_storage.h
+++ b/components/esp_tee/subproject/components/tee_sec_storage/include/esp_tee_sec_storage.h
@@ -16,6 +16,8 @@ extern "C" {
 #include "esp_err.h"
 #include "esp_bit_defs.h"
 
+#include "sdkconfig.h"
+
 #if CONFIG_SECURE_TEE_SEC_STG_SUPPORT_SECP384R1_SIGN
 #define MAX_ECDSA_SUPPORTED_KEY_LEN         48   /*!< Maximum supported size for the ECDSA key (SECP384R1) */
 #else
@@ -25,6 +27,7 @@ extern "C" {
 
 #define SEC_STORAGE_FLAG_NONE               0      /*!< No flags */
 #define SEC_STORAGE_FLAG_WRITE_ONCE         BIT(0) /*!< Data can only be written once */
+#define SEC_STORAGE_FLAG_TEE_ONLY           BIT(1) /*!< Key is owned exclusively by the TEE */
 
 /**
  * @brief Enum to represent the type of key stored in the secure storage
@@ -97,6 +100,21 @@ typedef struct {
  * @return esp_err_t ESP_OK on success, appropriate error code otherwise.
  */
 esp_err_t esp_tee_sec_storage_init(void);
+
+/**
+ * @brief Check whether a key ID is owned exclusively by the TEE
+ *
+ * A key is TEE-owned if either:
+ *   - it refers to the reserved TEE attestation key
+ *     (`CONFIG_SECURE_TEE_ATT_KEY_STR_ID`); this also blocks the REE from
+ *     "squatting" the ID before the TEE creates the key, or
+ *   - the stored key carries the ::SEC_STORAGE_FLAG_TEE_ONLY flag.
+ *
+ * @param key_id  NULL-terminated key identifier string (may be NULL)
+ *
+ * @return true if the key is TEE-owned (REE access must be denied), false otherwise
+ */
+bool esp_tee_sec_storage_is_key_tee_owned(const char *key_id);
 #endif
 
 /**
@@ -145,11 +163,13 @@ esp_err_t esp_tee_sec_storage_ecdsa_get_pubkey(const esp_tee_sec_storage_key_cfg
  *
  * @param[in]  ctx      Pointer to the AEAD operation context
  * @param[out] iv       Pointer to the output buffer for the generated initialization vector
- * @param[in]  iv_len   Length of the initialization vector buffer
+ * @param[in]  iv_len   Length of the initialization vector buffer; must be exactly 12 bytes (96-bit IV, per NIST SP 800-38D)
  * @param[out] tag      Pointer to the authentication tag buffer
- * @param[in]  tag_len  Length of the authentication tag
+ * @param[in]  tag_len  Length of the authentication tag; must be 12 to 16 bytes (96- to 128-bit tag, per NIST SP 800-38D)
  * @param[out] output   Pointer to the output data buffer
  *
+ * @note Non-standard @p iv_len / @p tag_len values are rejected with ESP_ERR_INVALID_SIZE.
+ *
  * @return esp_err_t ESP_OK on success, appropriate error code otherwise.
  */
 esp_err_t esp_tee_sec_storage_aead_encrypt(const esp_tee_sec_storage_aead_ctx_t *ctx, uint8_t *iv, size_t iv_len, uint8_t *tag, size_t tag_len, uint8_t *output);
@@ -159,11 +179,13 @@ esp_err_t esp_tee_sec_storage_aead_encrypt(const esp_tee_sec_storage_aead_ctx_t
  *
  * @param[in]  ctx      Pointer to the AEAD operation context
  * @param[in]  iv       Pointer to the initialization vector used during encryption
- * @param[in]  iv_len   Length of the initialization vector
+ * @param[in]  iv_len   Length of the initialization vector; must be exactly 12 bytes (96-bit IV, per NIST SP 800-38D)
  * @param[in]  tag      Pointer to the authentication tag buffer
- * @param[in]  tag_len  Length of the authentication tag
+ * @param[in]  tag_len  Length of the authentication tag; must be 12 to 16 bytes (96- to 128-bit tag, per NIST SP 800-38D)
  * @param[out] output   Pointer to the output data buffer
  *
+ * @note Non-standard @p iv_len / @p tag_len values are rejected with ESP_ERR_INVALID_SIZE.
+ *
  * @return esp_err_t ESP_OK on success, appropriate error code otherwise.
  */
 esp_err_t esp_tee_sec_storage_aead_decrypt(const esp_tee_sec_storage_aead_ctx_t *ctx, const uint8_t *iv, size_t iv_len, const uint8_t *tag, size_t tag_len, uint8_t *output);
diff --git a/components/esp_tee/subproject/components/tee_sec_storage/tee_sec_storage.c b/components/esp_tee/subproject/components/tee_sec_storage/tee_sec_storage.c
index 8f01c8e3313..f4b61fe1800 100644
--- a/components/esp_tee/subproject/components/tee_sec_storage/tee_sec_storage.c
+++ b/components/esp_tee/subproject/components/tee_sec_storage/tee_sec_storage.c
@@ -37,6 +37,8 @@
 #define AES256_KEY_LEN                      32
 #define AES256_KEY_BITS                     (AES256_KEY_LEN * 8)
 #define AES256_GCM_IV_LEN                   12
+#define AES256_GCM_TAG_LEN_MIN             12   /* NIST SP800-38D general-use minimum (96-bit tag) */
+#define AES256_GCM_TAG_LEN_MAX             16   /* full GCM tag (128-bit) */
 #define ECDSA_SECP384R1_KEY_LEN             48
 #define ECDSA_SECP256R1_KEY_LEN             32
 
@@ -285,6 +287,29 @@ static esp_err_t secure_storage_read(const char *key_id, void *data, size_t *len
     return nvs_get_blob(tee_nvs_hdl, key_id, data, len);
 }
 
+bool esp_tee_sec_storage_is_key_tee_owned(const char *key_id)
+{
+    if (key_id == NULL) {
+        return false;
+    }
+
+    bool is_att_key = false, is_tee_only = false;
+    esp_err_t err = ESP_FAIL;
+
+#if CONFIG_SECURE_TEE_ATTESTATION
+    is_att_key = (strncmp(key_id, CONFIG_SECURE_TEE_ATT_KEY_STR_ID, NVS_KEY_NAME_MAX_SIZE) == 0);
+#endif
+
+    sec_stg_key_t keyctx = {};
+    size_t keyctx_len = sizeof(keyctx);
+
+    err = secure_storage_read(key_id, (void *)&keyctx, &keyctx_len);
+    is_tee_only = (err == ESP_OK) && ((keyctx.flags & SEC_STORAGE_FLAG_TEE_ONLY) != 0);
+    mbedtls_platform_zeroize(&keyctx, sizeof(keyctx));
+
+    return (is_att_key || is_tee_only);
+}
+
 /* ---------------------------------------------- Interface APIs ------------------------------------------------- */
 
 esp_err_t esp_tee_sec_storage_init(void)
@@ -658,8 +683,16 @@ static esp_err_t tee_sec_storage_crypt_common(const char *key_id, const uint8_t
         return ESP_ERR_INVALID_ARG;
     }
 
-    if (len == 0 || tag_len == 0 || iv_len == 0) {
-        ESP_LOGE(TAG, "Invalid input/tag/iv length");
+    if (len == 0) {
+        ESP_LOGE(TAG, "Invalid input length");
+        return ESP_ERR_INVALID_SIZE;
+    }
+
+    /* Enforce standard AES-GCM parameters */
+    if (iv_len != AES256_GCM_IV_LEN ||
+            tag_len < AES256_GCM_TAG_LEN_MIN || tag_len > AES256_GCM_TAG_LEN_MAX) {
+        ESP_LOGE(TAG, "Non-standard GCM iv_len(%u)/tag_len(%u) rejected",
+                 (unsigned)iv_len, (unsigned)tag_len);
         return ESP_ERR_INVALID_SIZE;
     }
 
diff --git a/components/esp_tee/subproject/main/common/multi_heap.c b/components/esp_tee/subproject/main/common/multi_heap.c
index e735ec73037..f84d2bed1a7 100644
--- a/components/esp_tee/subproject/main/common/multi_heap.c
+++ b/components/esp_tee/subproject/main/common/multi_heap.c
@@ -6,6 +6,7 @@
 #include <assert.h>
 #include <stdio.h>
 #include <stdbool.h>
+#include <string.h>
 #include "rom_patch_tlsf.h"
 #include "esp_rom_sys.h"
 #include "tlsf_block_functions.h"
@@ -63,6 +64,9 @@ esp_err_t esp_tee_heap_init(void *start_ptr, size_t size)
         return ESP_ERR_INVALID_SIZE;
     }
 
+    /* Zeroize the entire region before registering it as the TEE heap*/
+    memset(start_ptr, 0, size);
+
 #if CONFIG_IDF_TARGET_ESP32C6 || CONFIG_IDF_TARGET_ESP32H2
     void *heap = tlsf_create_with_pool(start_ptr + sizeof(heap_t), usable_size);
     size_t overhead = tlsf_size();
@@ -227,7 +231,7 @@ void esp_tee_heap_dump_info(void)
 
 /* Definitions for functions from the heap component, used in files shared with ESP-IDF */
 
-void *heap_caps_malloc(size_t alignment, size_t size, uint32_t caps)
+void *heap_caps_malloc(size_t size, uint32_t caps)
 {
     (void) caps;
     return esp_tee_heap_malloc(size);
diff --git a/components/esp_tee/subproject/main/core/esp_secure_services.c b/components/esp_tee/subproject/main/core/esp_secure_services.c
index b56b0c7c28c..2a335938407 100644
--- a/components/esp_tee/subproject/main/core/esp_secure_services.c
+++ b/components/esp_tee/subproject/main/core/esp_secure_services.c
@@ -592,17 +592,24 @@ int _ss_esp_tee_ota_end(void)
  */
 esp_err_t _ss_esp_tee_sec_storage_clear_key(const char *key_id)
 {
+    bool valid_arg = !esp_tee_sec_storage_is_key_tee_owned(key_id);
+    if (!valid_arg) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    ESP_FAULT_ASSERT(valid_arg);
+
     return esp_tee_sec_storage_clear_key(key_id);
 }
 
 esp_err_t _ss_esp_tee_sec_storage_gen_key(const esp_tee_sec_storage_key_cfg_t *cfg)
 {
-    bool valid_addr = esp_tee_buf_in_ree(cfg, sizeof(esp_tee_sec_storage_key_cfg_t));
-
-    if (!valid_addr) {
+    bool valid_arg = esp_tee_buf_in_ree(cfg, sizeof(esp_tee_sec_storage_key_cfg_t)) &&
+                     !(cfg->flags & SEC_STORAGE_FLAG_TEE_ONLY) &&
+                     !esp_tee_sec_storage_is_key_tee_owned(cfg->id);
+    if (!valid_arg) {
         return ESP_ERR_INVALID_ARG;
     }
-    ESP_FAULT_ASSERT(valid_addr);
+    ESP_FAULT_ASSERT(valid_arg);
 
     return esp_tee_sec_storage_gen_key(cfg);
 }
diff --git a/components/esp_tee/subproject/main/core/esp_secure_services_iram.c b/components/esp_tee/subproject/main/core/esp_secure_services_iram.c
index b5030720fc4..cf7d56e98b6 100644
--- a/components/esp_tee/subproject/main/core/esp_secure_services_iram.c
+++ b/components/esp_tee/subproject/main/core/esp_secure_services_iram.c
@@ -8,6 +8,7 @@
 
 #include "esp_err.h"
 #include "esp_log.h"
+#include "esp_macros.h"
 #include "esp_fault.h"
 
 #include "hal/mmu_types.h"
@@ -38,6 +39,9 @@
 
 static __attribute__((unused)) const char *TAG = "esp_tee_sec_srv_iram";
 
+#define ALIGN_UP(num, align)   (((num) + ((align) - 1)) & ~((align) - 1))
+#define ALIGN_DOWN(num, align) ((num) & ~((align) - 1))
+
 /* ---------------------------------------------- Interrupts ------------------------------------------------- */
 
 #if SOC_INT_CLIC_SUPPORTED
@@ -191,67 +195,69 @@ void _ss_wdt_hal_deinit(wdt_hal_context_t *hal)
  */
 esp_err_t _ss_esp_tee_sec_storage_ecdsa_sign(const esp_tee_sec_storage_key_cfg_t *cfg, const uint8_t *hash, size_t hlen, esp_tee_sec_storage_ecdsa_sign_t *out_sign)
 {
-    bool valid_addr = (esp_tee_buf_in_ree(cfg, sizeof(esp_tee_sec_storage_key_cfg_t)) &&
-                       esp_tee_buf_in_ree(hash, hlen) &&
-                       esp_tee_buf_in_ree(out_sign, sizeof(esp_tee_sec_storage_ecdsa_sign_t)));
-
-    if (!valid_addr) {
+    bool valid_arg = (esp_tee_buf_in_ree(cfg, sizeof(esp_tee_sec_storage_key_cfg_t)) &&
+                      esp_tee_buf_in_ree(hash, hlen) &&
+                      esp_tee_buf_in_ree(out_sign, sizeof(esp_tee_sec_storage_ecdsa_sign_t)) &&
+                      !esp_tee_sec_storage_is_key_tee_owned(cfg->id));
+    if (!valid_arg) {
         return ESP_ERR_INVALID_ARG;
     }
-    ESP_FAULT_ASSERT(valid_addr);
+    ESP_FAULT_ASSERT(valid_arg);
 
     return esp_tee_sec_storage_ecdsa_sign(cfg, hash, hlen, out_sign);
 }
 
 esp_err_t _ss_esp_tee_sec_storage_ecdsa_get_pubkey(const esp_tee_sec_storage_key_cfg_t *cfg, esp_tee_sec_storage_ecdsa_pubkey_t *out_pubkey)
 {
-    bool valid_addr = (esp_tee_buf_in_ree(cfg, sizeof(esp_tee_sec_storage_key_cfg_t)) &&
-                       esp_tee_buf_in_ree(out_pubkey, sizeof(esp_tee_sec_storage_ecdsa_pubkey_t)));
-
-    if (!valid_addr) {
+    bool valid_arg = (esp_tee_buf_in_ree(cfg, sizeof(esp_tee_sec_storage_key_cfg_t)) &&
+                      esp_tee_buf_in_ree(out_pubkey, sizeof(esp_tee_sec_storage_ecdsa_pubkey_t)) &&
+                      !esp_tee_sec_storage_is_key_tee_owned(cfg->id));
+    if (!valid_arg) {
         return ESP_ERR_INVALID_ARG;
     }
-    ESP_FAULT_ASSERT(valid_addr);
+    ESP_FAULT_ASSERT(valid_arg);
 
     return esp_tee_sec_storage_ecdsa_get_pubkey(cfg, out_pubkey);
 }
 
 esp_err_t _ss_esp_tee_sec_storage_aead_encrypt(const esp_tee_sec_storage_aead_ctx_t *ctx, uint8_t *iv, size_t iv_len, uint8_t *tag, size_t tag_len, uint8_t *output)
 {
-    bool valid_addr = (esp_tee_buf_in_ree(ctx, sizeof(esp_tee_sec_storage_aead_ctx_t)) &&
-                       esp_tee_buf_in_ree(ctx->input, ctx->input_len) &&
-                       esp_tee_buf_in_ree(iv, iv_len) &&
-                       esp_tee_buf_in_ree(tag, tag_len) &&
-                       esp_tee_buf_in_ree(output, ctx->input_len));
+    bool valid_arg = (esp_tee_buf_in_ree(ctx, sizeof(esp_tee_sec_storage_aead_ctx_t)) &&
+                      esp_tee_buf_in_ree(ctx->input, ctx->input_len) &&
+                      esp_tee_buf_in_ree(iv, iv_len) &&
+                      esp_tee_buf_in_ree(tag, tag_len) &&
+                      esp_tee_buf_in_ree(output, ctx->input_len) &&
+                      !esp_tee_sec_storage_is_key_tee_owned(ctx->key_id));
 
     if (ctx->aad_len != 0) {
-        valid_addr &= esp_tee_buf_in_ree(ctx->aad, ctx->aad_len);
+        valid_arg &= esp_tee_buf_in_ree(ctx->aad, ctx->aad_len);
     }
 
-    if (!valid_addr) {
+    if (!valid_arg) {
         return ESP_ERR_INVALID_ARG;
     }
-    ESP_FAULT_ASSERT(valid_addr);
+    ESP_FAULT_ASSERT(valid_arg);
 
     return esp_tee_sec_storage_aead_encrypt(ctx, iv, iv_len, tag, tag_len, output);
 }
 
 esp_err_t _ss_esp_tee_sec_storage_aead_decrypt(const esp_tee_sec_storage_aead_ctx_t *ctx, const uint8_t *iv, size_t iv_len, const uint8_t *tag, size_t tag_len, uint8_t *output)
 {
-    bool valid_addr = (esp_tee_buf_in_ree(ctx, sizeof(esp_tee_sec_storage_aead_ctx_t)) &&
-                       esp_tee_buf_in_ree(ctx->input, ctx->input_len) &&
-                       esp_tee_buf_in_ree(iv, iv_len) &&
-                       esp_tee_buf_in_ree(tag, tag_len) &&
-                       esp_tee_buf_in_ree(output, ctx->input_len));
+    bool valid_arg = (esp_tee_buf_in_ree(ctx, sizeof(esp_tee_sec_storage_aead_ctx_t)) &&
+                      esp_tee_buf_in_ree(ctx->input, ctx->input_len) &&
+                      esp_tee_buf_in_ree(iv, iv_len) &&
+                      esp_tee_buf_in_ree(tag, tag_len) &&
+                      esp_tee_buf_in_ree(output, ctx->input_len) &&
+                      !esp_tee_sec_storage_is_key_tee_owned(ctx->key_id));
 
     if (ctx->aad_len != 0) {
-        valid_addr &= esp_tee_buf_in_ree(ctx->aad, ctx->aad_len);
+        valid_arg &= esp_tee_buf_in_ree(ctx->aad, ctx->aad_len);
     }
 
-    if (!valid_addr) {
+    if (!valid_arg) {
         return ESP_ERR_INVALID_ARG;
     }
-    ESP_FAULT_ASSERT(valid_addr);
+    ESP_FAULT_ASSERT(valid_arg);
 
     return esp_tee_sec_storage_aead_decrypt(ctx, iv, iv_len, tag, tag_len, output);
 }
@@ -274,11 +280,32 @@ esp_err_t _ss_esp_tee_sec_storage_ecdsa_sign_pbkdf2(const esp_tee_sec_storage_pb
 
 /* ---------------------------------------------- MMU HAL ------------------------------------------------- */
 
+static bool tee_ree_ext_vaddr_ok(uint32_t mmu_id, uint32_t vaddr, uint32_t len)
+{
+    uint32_t page = mmu_hal_pages_to_bytes(mmu_id, 1);
+    uint32_t map_len = ALIGN_UP(len, page);
+
+    return (len != 0 && map_len >= len && (vaddr % page == 0) &&
+            mmu_hal_check_valid_ext_vaddr_region(mmu_id, vaddr, map_len,
+                                                 MMU_VADDR_DATA | MMU_VADDR_INSTRUCTION) &&
+            !esp_tee_flash_check_vrange_in_tee_region(vaddr, map_len));
+}
+
+static bool tee_ree_ext_paddr_ok(uint32_t mmu_id, uint32_t paddr, uint32_t len)
+{
+    uint32_t page = mmu_hal_pages_to_bytes(mmu_id, 1);
+    uint32_t map_len = ALIGN_UP(len, page);
+
+    return (len != 0 && map_len >= len && (paddr % page == 0) &&
+            mmu_hal_check_valid_paddr_region(mmu_id, paddr, map_len) &&
+            !esp_tee_flash_check_prange_in_tee_region(paddr, map_len));
+}
+
 void _ss_mmu_hal_map_region(uint32_t mmu_id, mmu_target_t mem_type, uint32_t vaddr,
                             uint32_t paddr, uint32_t len, uint32_t *out_len)
 {
-    bool valid_addr = (!esp_tee_flash_check_vrange_in_tee_region(vaddr, len) &&
-                       !esp_tee_flash_check_prange_in_tee_region(paddr, len) &&
+    bool valid_addr = (tee_ree_ext_vaddr_ok(mmu_id, vaddr, len) &&
+                       tee_ree_ext_paddr_ok(mmu_id, paddr, len) &&
                        esp_tee_buf_in_ree(out_len, sizeof(uint32_t)));
 
     if (!valid_addr) {
@@ -292,20 +319,21 @@ void _ss_mmu_hal_map_region(uint32_t mmu_id, mmu_target_t mem_type, uint32_t vad
 
 void _ss_mmu_hal_unmap_region(uint32_t mmu_id, uint32_t vaddr, uint32_t len)
 {
-    bool vaddr_chk = esp_tee_flash_check_vrange_in_tee_region(vaddr, len);
+    bool valid_addr = tee_ree_ext_vaddr_ok(mmu_id, vaddr, len);
 
-    if (vaddr_chk) {
+    if (!valid_addr) {
         ESP_LOGD(TAG, "[%s] Illegal flash access at 0x%08x", __func__, vaddr);
         return;
     }
-    ESP_FAULT_ASSERT(!vaddr_chk);
+    ESP_FAULT_ASSERT(valid_addr);
 
     mmu_hal_unmap_region(mmu_id, vaddr, len);
 }
 
 bool _ss_mmu_hal_vaddr_to_paddr(uint32_t mmu_id, uint32_t vaddr, uint32_t *out_paddr, mmu_target_t *out_target)
 {
-    bool valid_addr = (!esp_tee_flash_check_vaddr_in_tee_region(vaddr) &&
+    uint32_t page = mmu_hal_pages_to_bytes(mmu_id, 1);
+    bool valid_addr = (tee_ree_ext_vaddr_ok(mmu_id, ALIGN_DOWN(vaddr, page), 1) &&
                        esp_tee_buf_in_ree(out_paddr, sizeof(uint32_t)) &&
                        esp_tee_buf_in_ree(out_target, sizeof(mmu_target_t)));
 
@@ -319,7 +347,8 @@ bool _ss_mmu_hal_vaddr_to_paddr(uint32_t mmu_id, uint32_t vaddr, uint32_t *out_p
 
 bool _ss_mmu_hal_paddr_to_vaddr(uint32_t mmu_id, uint32_t paddr, mmu_target_t target, mmu_vaddr_t type, uint32_t *out_vaddr)
 {
-    bool valid_addr = (!esp_tee_flash_check_paddr_in_tee_region(paddr) &&
+    bool valid_addr = (mmu_hal_check_valid_paddr_region(mmu_id, paddr, 1) &&
+                       !esp_tee_flash_check_paddr_in_tee_region(paddr) &&
                        esp_tee_buf_in_ree(out_vaddr, sizeof(uint32_t)));
 
     if (!valid_addr) {
diff --git a/components/esp_tee/subproject/main/core/esp_tee_init.c b/components/esp_tee/subproject/main/core/esp_tee_init.c
index d42e155f579..998ea0c1134 100644
--- a/components/esp_tee/subproject/main/core/esp_tee_init.c
+++ b/components/esp_tee/subproject/main/core/esp_tee_init.c
@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2024-2026 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -26,6 +26,9 @@
 
 /* TEE symbols */
 extern uint32_t _tee_stack;
+extern uint32_t _tee_stack_bottom;
+extern uint32_t _tee_intr_stack;
+extern uint32_t _tee_intr_stack_bottom;
 extern uint32_t _tee_bss_start;
 extern uint32_t _tee_bss_end;
 extern uint32_t _tee_s_intr_handler;
@@ -119,6 +122,9 @@ void __attribute__((noreturn)) esp_tee_init(uint32_t ree_entry_addr, uint32_t re
 {
     /* Clear BSS */
     memset(&_tee_bss_start, 0, (&_tee_bss_end - &_tee_bss_start) * sizeof(_tee_bss_start));
+    /* Clear the TEE stack and interrupt stack */
+    memset(&_tee_stack_bottom, 0, (&_tee_stack - &_tee_stack_bottom) * sizeof(_tee_stack_bottom));
+    memset(&_tee_intr_stack_bottom, 0, (&_tee_intr_stack - &_tee_intr_stack_bottom) * sizeof(_tee_intr_stack_bottom));
 
     static uint32_t btld_sp;
 
diff --git a/components/esp_tee/test_apps/tee_cli_app/main/tee_srv_sec_str.c b/components/esp_tee/test_apps/tee_cli_app/main/tee_srv_sec_str.c
index 7aaa2edeb13..de49b5ff24b 100644
--- a/components/esp_tee/test_apps/tee_cli_app/main/tee_srv_sec_str.c
+++ b/components/esp_tee/test_apps/tee_cli_app/main/tee_srv_sec_str.c
@@ -204,7 +204,7 @@ static int tee_sec_stg_gen_key(int argc, char **argv)
 
     err = esp_tee_sec_storage_clear_key(cfg.id);
     if (err != ESP_OK && err != ESP_ERR_NOT_FOUND) {
-        ESP_LOGE(TAG, "Failed to clear key %d!", cfg.id);
+        ESP_LOGE(TAG, "Failed to clear key %s!", cfg.id);
         goto exit;
     }
 
diff --git a/components/esp_tee/test_apps/tee_cli_app/pytest_tee_cli.py b/components/esp_tee/test_apps/tee_cli_app/pytest_tee_cli.py
index 2acdcc3bf30..226bc637091 100644
--- a/components/esp_tee/test_apps/tee_cli_app/pytest_tee_cli.py
+++ b/components/esp_tee/test_apps/tee_cli_app/pytest_tee_cli.py
@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2024-2026 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
 import hashlib
 import http.server
@@ -135,10 +135,6 @@ def test_tee_cli_attestation(dut: Dut) -> None:
     dut.expect('ESP-TEE: Secure services demonstration', timeout=30)
     time.sleep(1)
 
-    att_key_id = dut.app.sdkconfig.get('SECURE_TEE_ATT_KEY_STR_ID')
-    dut.write(f'tee_sec_stg_gen_key {att_key_id} 1')
-    dut.expect(r'Generated ECDSA_SECP256R1 key with ID (\S+)', timeout=30)
-
     # Get the Entity Attestation token from TEE and verify its signature
     dut.write('tee_att_info')
     dut.expect(r'Attestation token - Length: (\d+)', timeout=30)
diff --git a/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.minimal_tee b/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.minimal_tee
index eb2f53d45c5..2cff4b58aa5 100644
--- a/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.minimal_tee
+++ b/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.minimal_tee
@@ -5,8 +5,8 @@ CONFIG_SECURE_TEE_SEC_STG_EFUSE_HMAC_KEY_ID=5
 # Reducing TEE I/DRAM sizes
 # 24KB
 CONFIG_SECURE_TEE_IRAM_SIZE=0x6000
-# 16KB
-CONFIG_SECURE_TEE_DRAM_SIZE=0x4000
+# 17KB
+CONFIG_SECURE_TEE_DRAM_SIZE=0x4400
 
 # Disable TEE logs (also disable all panic logs)
 CONFIG_SECURE_TEE_DEBUG_MODE=n
diff --git a/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.release b/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.release
index f4c39acfebb..b6b8fd811d3 100644
--- a/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.release
+++ b/components/esp_tee/test_apps/tee_cli_app/sdkconfig.ci.release
@@ -2,8 +2,8 @@
 # builds across various configurations - and is not intended for production use.
 
 # Reducing TEE IRAM size
-# 30KB
-CONFIG_SECURE_TEE_IRAM_SIZE=0x7800
+# 31KB
+CONFIG_SECURE_TEE_IRAM_SIZE=0x7C00
 
 # TEE Secure Storage: Release mode
 CONFIG_SECURE_TEE_SEC_STG_MODE_RELEASE=y
diff --git a/components/esp_tee/test_apps/tee_test_fw/conftest.py b/components/esp_tee/test_apps/tee_test_fw/conftest.py
index b025bc4db43..585c739e042 100644
--- a/components/esp_tee/test_apps/tee_test_fw/conftest.py
+++ b/components/esp_tee/test_apps/tee_test_fw/conftest.py
@@ -418,6 +418,7 @@ class TEESerial(IdfSerial):
             'type': 'ecdsa_p256',
             'input': 'ecdsa_p256_key.pem',
             'write_once': True,
+            'tee_only': True,
             'b64': (
                 'LS0tLS1CRUdJTiBFQyBQUklWQVRFIEtFWS0tLS0tCk1IY0NBUUVFSUlNU1VpUktHaVZjSTIvbUZFekI3eXRIOVJj'
                 'd0wyUThkNDhONHNFUHFYc0RvQW9HQ0NxR1NNNDkKQXdFSG9VUURRZ0FFSkYxYXRZQUxrdnB4cCt4N3c1dmVPQ1Vj'
@@ -493,6 +494,7 @@ class TEESerial(IdfSerial):
             [sys.executable, ESP_TEE_SEC_STG_KEYGEN, '-k', entry['type'], '-o', str(tmp_dir / f'{entry["key"]}.bin')]
             + (['-i', entry['input']] if entry['input'] else [])
             + (['--write-once'] if entry['write_once'] else [])
+            + (['--tee-only'] if entry.get('tee_only') else [])
             for entry in self.KEY_DEFS
         ]
 
diff --git a/components/esp_tee/test_apps/tee_test_fw/main/test_esp_tee_sec_stg.c b/components/esp_tee/test_apps/tee_test_fw/main/test_esp_tee_sec_stg.c
index c5ea5f79781..55dd7ff4b7e 100644
--- a/components/esp_tee/test_apps/tee_test_fw/main/test_esp_tee_sec_stg.c
+++ b/components/esp_tee/test_apps/tee_test_fw/main/test_esp_tee_sec_stg.c
@@ -365,6 +365,38 @@ TEST_CASE("Test TEE Secure Storage - Null Pointer and Zero Length", "[sec_storag
     TEST_ESP_OK(esp_tee_sec_storage_clear_key(key_cfg.id));
 }
 
+#if CONFIG_SECURE_TEE_ATTESTATION
+TEST_CASE("Test TEE Secure Storage - Attestation key is not REE-accessible", "[sec_storage]")
+{
+    const char *att_key_id = CONFIG_SECURE_TEE_ATT_KEY_STR_ID;
+
+    esp_tee_sec_storage_key_cfg_t key_cfg = {
+        .id = att_key_id,
+        .type = ESP_SEC_STG_KEY_ECDSA_SECP256R1
+    };
+
+    uint8_t digest[SHA256_DIGEST_SZ];
+    esp_fill_random(digest, sizeof(digest));
+
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_gen_key(&key_cfg));
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_clear_key(att_key_id));
+
+    esp_tee_sec_storage_ecdsa_sign_t sign = {};
+    esp_tee_sec_storage_ecdsa_pubkey_t pubkey = {};
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_ecdsa_sign(&key_cfg, digest, sizeof(digest), &sign));
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_ecdsa_get_pubkey(&key_cfg, &pubkey));
+
+    uint8_t data[31], tag[12], iv[12];
+    esp_tee_sec_storage_aead_ctx_t aead_ctx = {
+        .key_id = att_key_id,
+        .input = data,
+        .input_len = sizeof(data),
+    };
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_aead_encrypt(&aead_ctx, iv, sizeof(iv), tag, sizeof(tag), data));
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_aead_decrypt(&aead_ctx, iv, sizeof(iv), tag, sizeof(tag), data));
+}
+#endif
+
 TEST_CASE("Test TEE Secure Storage - Verify data encryption", "[sec_storage_encr]")
 {
     ESP_LOGI(TAG, "Populating NVS-based TEE Secure Storage; encrypted with XTS-AES-512");
@@ -423,6 +455,22 @@ TEST_CASE("Test TEE Secure Storage - WRITE_ONCE keys", "[sec_storage]")
     TEST_ESP_ERR(ESP_ERR_INVALID_STATE, esp_tee_sec_storage_clear_key(key_cfg.id));
 }
 
+TEST_CASE("Test TEE Secure Storage - TEE_ONLY keys", "[sec_storage]")
+{
+    const char *key_id = "key_id_tee_only";
+    esp_tee_sec_storage_key_cfg_t key_cfg = {
+        .id = key_id,
+        .type = ESP_SEC_STG_KEY_ECDSA_SECP256R1,
+        .flags = SEC_STORAGE_FLAG_TEE_ONLY,
+    };
+
+    esp_err_t err = esp_tee_sec_storage_clear_key(key_cfg.id);
+    TEST_ASSERT_TRUE(err == ESP_OK || err == ESP_ERR_NOT_FOUND);
+
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_gen_key(&key_cfg));
+    TEST_ESP_ERR(ESP_ERR_NOT_FOUND, esp_tee_sec_storage_clear_key(key_cfg.id));
+}
+
 static void test_aead_encrypt_decrypt(const char *key_id, const uint8_t *input, size_t len)
 {
     uint8_t *ciphertext = heap_caps_malloc(len, MALLOC_CAP_8BIT | MALLOC_CAP_INTERNAL);
@@ -524,10 +572,19 @@ TEST_CASE("Test TEE Secure Storage - Host-generated keys", "[sec_storage_host_ke
     size_t token_len = 0;
     TEST_ESP_OK(psa_initial_attest_get_token(auth_challenge, challenge_size, token_buf, token_buf_size, &token_len));
     free(token_buf);
-
-    const char *attest_key_id  = "attest_key";
-    TEST_ESP_ERR(ESP_ERR_INVALID_STATE, esp_tee_sec_storage_clear_key(attest_key_id));
 #endif /* CONFIG_SECURE_TEE_ATTESTATION */
+
+    const char *attest_key_id = "attest_key";
+    esp_tee_sec_storage_key_cfg_t attest_cfg = {
+        .id   = attest_key_id,
+        .type = ESP_SEC_STG_KEY_ECDSA_SECP256R1,
+    };
+    esp_tee_sec_storage_ecdsa_sign_t attest_sign = {0};
+    esp_tee_sec_storage_ecdsa_pubkey_t attest_pubkey = {0};
+
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_ecdsa_sign(&attest_cfg, digest_buf, SHA256_DIGEST_SZ, &attest_sign));
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_ecdsa_get_pubkey(&attest_cfg, &attest_pubkey));
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, esp_tee_sec_storage_clear_key(attest_key_id));
 }
 
 #if CONFIG_MBEDTLS_TEE_SEC_STG_ECDSA_SIGN
diff --git a/components/hal/include/hal/mmu_hal.h b/components/hal/include/hal/mmu_hal.h
index 779af2d068e..82551ea7152 100644
--- a/components/hal/include/hal/mmu_hal.h
+++ b/components/hal/include/hal/mmu_hal.h
@@ -149,6 +149,18 @@ bool mmu_hal_paddr_to_vaddr(uint32_t mmu_id, uint32_t paddr, mmu_target_t target
  */
 bool mmu_hal_check_valid_ext_vaddr_region(uint32_t mmu_id, uint32_t vaddr_start, uint32_t len, mmu_vaddr_t type);
 
+/**
+ * Check if the paddr region is valid
+ *
+ * @param mmu_id      MMU ID
+ * @param paddr_start start of the physical address
+ * @param len         length, in bytes
+ *
+ * @return
+ *         True for valid
+ */
+bool mmu_hal_check_valid_paddr_region(uint32_t mmu_id, uint32_t paddr_start, uint32_t len);
+
 #if SOC_MMU_PER_EXT_MEM_TARGET
 /**
  * Get MMU ID from MMU target
diff --git a/components/hal/mmu_hal.c b/components/hal/mmu_hal.c
index 5c83a9681fd..0cd593d8efa 100644
--- a/components/hal/mmu_hal.c
+++ b/components/hal/mmu_hal.c
@@ -197,6 +197,11 @@ bool mmu_hal_check_valid_ext_vaddr_region(uint32_t mmu_id, uint32_t vaddr_start,
     return mmu_ll_check_valid_ext_vaddr_region(mmu_id, vaddr_start, len, type);
 }
 
+bool mmu_hal_check_valid_paddr_region(uint32_t mmu_id, uint32_t paddr_start, uint32_t len)
+{
+    return mmu_ll_check_valid_paddr_region(mmu_id, paddr_start, len);
+}
+
 #if SOC_MMU_PER_EXT_MEM_TARGET
 uint32_t mmu_hal_get_id_from_target(mmu_target_t target)
 {
diff --git a/docs/en/security/tee/tee-attestation.rst b/docs/en/security/tee/tee-attestation.rst
index 2d45bcf9a18..02cca2b9125 100644
--- a/docs/en/security/tee/tee-attestation.rst
+++ b/docs/en/security/tee/tee-attestation.rst
@@ -14,6 +14,10 @@ To ensure security, the EAT is cryptographically protected. The remote relying p
 
   - Support for Attestation can be toggled using the option :ref:`CONFIG_SECURE_TEE_ATTESTATION` (enabled by default).
 
+  - The attestation signing key (identified by :ref:`CONFIG_SECURE_TEE_ATT_KEY_STR_ID`) is owned exclusively by the TEE. When the TEE generates this key, it is marked with the ``SEC_STORAGE_FLAG_TEE_ONLY`` flag, and the REE is denied any access to it through the secure service interface - it cannot use the key for signing, regenerate it, or clear it. This ensures that the attestation evidence can only ever be signed from within the TEE.
+
+  - In addition, the reserved key ID is treated as TEE-owned even before the key exists, which prevents the REE from "squatting" the ID with a key of its own before the TEE provisions it. If the key is pre-provisioned as part of an NVS image (see :doc:`Secure Storage <tee-sec-storage>`), it **must** be generated with the ``--tee-only`` flag of the :component_file:`esp_tee_sec_stg_keygen.py<esp_tee/scripts/esp_tee_sec_stg_keygen/esp_tee_sec_stg_keygen.py>`  tool.
+
 Attestation Flow
 ----------------
 
diff --git a/examples/security/tee/tee_secure_storage/main/tee_main.c b/examples/security/tee/tee_secure_storage/main/tee_main.c
index aebdf0e1c2b..e24433cf933 100644
--- a/examples/security/tee/tee_secure_storage/main/tee_main.c
+++ b/examples/security/tee/tee_secure_storage/main/tee_main.c
@@ -93,7 +93,7 @@ static void example_tee_sec_stg_sign_verify(void *pvParameter)
 
     esp_err_t err = esp_tee_sec_storage_clear_key(cfg.id);
     if (err != ESP_OK && err != ESP_ERR_NOT_FOUND) {
-        ESP_LOGE(TAG, "Failed to clear key %d!", cfg.id);
+        ESP_LOGE(TAG, "Failed to clear key %s!", cfg.id);
         goto exit;
     }
 
@@ -186,7 +186,7 @@ static void example_tee_sec_stg_encrypt_decrypt(void *pvParameter)
 
     err = esp_tee_sec_storage_clear_key(cfg.id);
     if (err != ESP_OK && err != ESP_ERR_NOT_FOUND) {
-        ESP_LOGE(TAG, "Failed to clear key %d!", cfg.id);
+        ESP_LOGE(TAG, "Failed to clear key %s!", cfg.id);
         goto exit;
     }