diff --git a/lib/vquic/vquic.c b/lib/vquic/vquic.c
index 562a99e4fe..aa0011c577 100644
--- a/lib/vquic/vquic.c
+++ b/lib/vquic/vquic.c
@@ -145,6 +145,7 @@ static CURLcode do_sendmsg(struct Curl_cfilter *cf,
   if(pktlen > gsolen) {
     /* Only set this, when we need it. macOS, for example,
      * does not seem to like a msg_control of length 0. */
+    memset(msg_ctrl, 0, sizeof(msg_ctrl));
     msg.msg_control = msg_ctrl;
     assert(sizeof(msg_ctrl) >= CMSG_SPACE(sizeof(int)));
     msg.msg_controllen = CMSG_SPACE(sizeof(int));