--- a/crypto/rand/drbg_ctr.c
+++ b/crypto/rand/drbg_ctr.c
@@ -15,6 +15,7 @@
 #include "modes_local.h"
 #include "internal/thread_once.h"
 #include "rand_local.h"
+#include "sanitizers.h"
 
 /*
  * Implementation of NIST SP 800-90A CTR DRBG.
@@ -348,6 +349,7 @@ __owur static int drbg_ctr_generate(RAND_DRBG *drbg,
     }
 
     memset(out, 0, outlen);
+    __msan_unpoison(ctr->V, 16 * sizeof(char));
 
     do {
         if (!EVP_CipherInit_ex(ctr->ctx_ctr,