title: Missing bounds check in 9p message handling
description: The implementation of lib9p's handling of RWALK messages was missing a bounds check needed when unpacking the message contents.  The missing check means that the receipt of a specially crafted message will cause lib9p to overwrite unrelated memory.
The bug can be triggered by a malicious bhyve guest kernel to overwrite memory in the bhyve(8) process.  This could potentially lead to user-mode code execution on the host, subject to bhyve's Capsicum sandbox.
affected:
{
defaultStatus: unknown
modules: lib9p
product: FreeBSD
vendor: FreeBSD
versions:
lessThan: p1, status: affected, version: 13.1-RELEASE, versionType: release
lessThan: p12, status: affected, version: 13.0-RELEASE, versionType: release
}