diff --git a/src/spdm/spdm_tcg.c b/src/spdm/spdm_tcg.c
index e80184bb..10ea96ca 100644
--- a/src/spdm/spdm_tcg.c
+++ b/src/spdm/spdm_tcg.c
@@ -204,6 +204,9 @@ int wolfSPDM_BuildVendorDefined(
     if (vdCode == NULL || outBuf == NULL) {
         return WOLFSPDM_E_INVALID_ARG;
     }
+    if (payload == NULL && payloadSz != 0) {
+        return WOLFSPDM_E_INVALID_ARG;
+    }
 
     /* SPDM VENDOR_DEFINED_REQUEST format:
      * SPDMVersion(1) + reqRspCode(1) + param1(1) + param2(1) +