diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 0efebb40ce..96547e04dc 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3997,7 +3997,7 @@ psa_status_t psa_cipher_generate_iv(psa_cipher_operation_t *operation,
 {
     psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
     uint8_t local_iv[PSA_CIPHER_IV_MAX_SIZE];
-    size_t default_iv_length;
+    size_t default_iv_length = 0;
 
     if (operation->id == 0) {
         status = PSA_ERROR_BAD_STATE;
@@ -4604,7 +4604,7 @@ psa_status_t psa_aead_generate_nonce(psa_aead_operation_t *operation,
 {
     psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
     uint8_t local_nonce[PSA_AEAD_NONCE_MAX_SIZE];
-    size_t required_nonce_size;
+    size_t required_nonce_size = 0;
 
     *nonce_length = 0;
 
diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index 7c16e10e99..8b82297c66 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -246,7 +246,7 @@ int mbedtls_ssl_cache_set(void *data,
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
     mbedtls_ssl_cache_entry *cur;
 
-    size_t session_serialized_len;
+    size_t session_serialized_len = 0;
     unsigned char *session_serialized = NULL;
 
 #if defined(MBEDTLS_THREADING_C)
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 182443a5e9..36b01ce884 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -9672,7 +9672,7 @@ void persistent_key_load_key_from_storage(data_t *data,
     unsigned char *first_export = NULL;
     unsigned char *second_export = NULL;
     size_t export_size = PSA_EXPORT_KEY_OUTPUT_SIZE(type, bits);
-    size_t first_exported_length;
+    size_t first_exported_length = 0;
     size_t second_exported_length;
 
     if (usage_flags & PSA_KEY_USAGE_EXPORT) {