diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index 05703ef65c1..7184e47ba62 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -1699,6 +1699,9 @@ sockargs(mp, buf, buflen, type)
 	struct mbuf *m;
 	int error;
 
+	if (buflen < 0)
+		return (EINVAL);
+
 	if (buflen > MLEN) {
 #ifdef COMPAT_OLDSOCK
 		if (type == MT_SONAME && buflen <= 112)