diff --git a/Logan/mbedtls/library/x509_create.c b/Logan/mbedtls/library/x509_create.c
index df20ec8e..3da2d1c6 100644
--- a/Logan/mbedtls/library/x509_create.c
+++ b/Logan/mbedtls/library/x509_create.c
@@ -168,6 +168,10 @@ int mbedtls_x509_set_extension( mbedtls_asn1_named_data **head, const char *oid,
 {
     mbedtls_asn1_named_data *cur;
 
+    if (val_len > (SIZE_MAX  - 1)) {
+        return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
+    }
+
     if( ( cur = mbedtls_asn1_store_named_data( head, oid, oid_len,
                                        NULL, val_len + 1 ) ) == NULL )
     {