diff --git a/crypto/cmp/cmp_msg.c b/crypto/cmp/cmp_msg.c
index c6c1927ebc0fa..8a7fb129db16f 100644
--- a/crypto/cmp/cmp_msg.c
+++ b/crypto/cmp/cmp_msg.c
@@ -119,7 +119,7 @@ X509_PUBKEY *OSSL_CMP_MSG_get0_certreq_publickey(const OSSL_CMP_MSG *msg)
         if ((tmpl = OSSL_CRMF_MSG_get0_tmpl(crm)) == NULL
             || (pubkey = OSSL_CRMF_CERTTEMPLATE_get0_publicKey(tmpl)) == NULL) {
             ERR_raise(ERR_LIB_CMP, CRMF_R_POPO_MISSING_PUBLIC_KEY);
-            return 0;
+            return NULL;
         }
         return pubkey;
     default: