--- /n/sources/plan9/sys/src/9k/port/devmnt.c	Thu Jan 27 13:38:26 2022
+++ /sys/src/9k/port/devmnt.c	Sun Mar 24 17:05:55 2024
@@ -867,7 +867,7 @@
 
 	/* read in the rest of the message, avoid ridiculous (for now) message sizes */
 	len = GBIT32(nb->rp);
-	if(len > mnt->msize){
+	if(len < BIT32SZ+BIT8SZ+BIT16SZ || len > mnt->msize){
 		qdiscard(mnt->q, qlen(mnt->q));
 		return -1;
 	}