diff --git a/src/dc_receive_imf.rs b/src/dc_receive_imf.rs
index 53f6d3e54..9a2e5a448 100644
--- a/src/dc_receive_imf.rs
+++ b/src/dc_receive_imf.rs
@@ -1724,7 +1724,7 @@ fn search_chat_ids_by_contact_ids(context: &Context, unsorted_contact_ids: &Vec<
                             matches = 0;
                             mismatches = 0;
                         }
-                        if contact_id == contact_ids[matches] {
+                        if matches < contact_ids.len() && contact_id == contact_ids[matches] {
                             matches += 1;
                         } else {
                             mismatches += 1;