diff --git a/testsuite/cbc-test.c b/testsuite/cbc-test.c
index 4917e95adf0fd7e0c12f54f78107d38090a28dcb..b7bd2dd2ff5cd3583b028b2c4596aa90bc5c5210 100644
--- a/testsuite/cbc-test.c
+++ b/testsuite/cbc-test.c
@@ -73,7 +73,7 @@ test_cbc_bulk(void)
 int
 test_main(void)
 {
-  uint8_t msg[2 * AES_BLOCK_SIZE] = "Listen, I'll say this only once!";
+  static const uint8_t msg[2 * AES_BLOCK_SIZE] = "Listen, I'll say this only once!";
   
   /* Intermediate values:
    *   iv XOR first message block: