pseudofs: Information Disclosure Vulnerability

Users of pseudofs please be advised of an Information Disclosure vulnerability that has been identified.
To view this vulnerability, possible remedies, and others please check out the Security Advisories at Critical Watch (

FreeBSD-SA-10:09.pseudofs: [FreeBSD-SA-10:09.pseudofs] pseudofs Information Disclosure
I. Problem Description

The pfs_getextattr(9) function, used by pseudofs for handling extended
attributes, attempts to unlock a mutex which was not previously locked.

II. Impact

On systems where a pseudofs-using filesystem is mounted and NULL page
mapping is allowed, an attacker can overwrite arbitrary memory locations
in the kernel with zero, and in certain cases execute arbitrary code in
the context of the kernel.

On systems which do not allow NULL page mapping, an attacker can cause the
FreeBSD kernel to panic.