diff --git a/kadmin/version4.c b/kadmin/version4.c
index 3bee407ea..a593e9d52 100644
--- a/kadmin/version4.c
+++ b/kadmin/version4.c
@@ -822,6 +822,13 @@ decode_packet(krb5_context context,
     off += _krb5_get_int(msg + off, &rlen, 4);
     memset(&authent, 0, sizeof(authent));
     authent.length = message.length - rlen - KADM_VERSIZE - 4;
+
+    if(authent.length >= MAX_KTXT_LEN) {
+	krb5_warnx(context, "received bad rlen (%lu)", (unsigned long)rlen);
+	make_you_loose_packet (KADM_LENGTH_ERROR, reply);
+	return;
+    }
+
     memcpy(authent.dat, (char*)msg + off, authent.length);
     off += authent.length;