FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

FreeBSD -- Missing bounds check in 9p message handling

Affected packages
13.1 <= FreeBSD < 13.1_1
13.0 <= FreeBSD < 13.0_12


VuXML ID 8eaaf135-1893-11ed-9b22-002590c1f29c
Discovery 2022-08-09
Entry 2022-08-10

Problem 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.


CVE Name CVE-2022-23092
FreeBSD Advisory SA-22:12.lib9p