--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -123,7 +123,7 @@ static int msgbufmapped;
 int msgbuftrigger;
 
-static int unprivileged_read_msgbuf = 1;
+static int unprivileged_read_msgbuf = 0;
 TUNABLE_INT("security.unprivileged_read_msgbuf", &unprivileged_read_msgbuf);