diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 602cd63..750f44f 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -121,6 +121,9 @@
 	if (nlmsg_len(nlh) < sizeof(*req))
 		return -EINVAL;
 
+	if (req->sdiag_family >= AF_MAX)
+		return -EINVAL;
+
 	hndl = sock_diag_lock_handler(req->sdiag_family);
 	if (hndl == NULL)
 		err = -ENOENT;