CVE-2026-72373: afs: Fix missing NULL pointer check in afs_break_some_callbacks()

CVE-2026-72373: afs: Fix missing NULL pointer check in afs_break_some_callbacks()

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

afs: Fix missing NULL pointer check in afs_break_some_callbacks()

Fix afs_break_some_callbacks() to check to see if afs_lookup_volume_rcu()
returned NULL (e.g. the specified volume is unknown).

The Linux kernel CVE team has assigned CVE-2026-72373 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.8 with commit 8230fd8217b7ea76f838ae88e4a5a8e54f37099f and fixed in 6.12.97 with commit a99a617701186dc68c7b330d35fc2253f48e2ab2
	Issue introduced in 5.8 with commit 8230fd8217b7ea76f838ae88e4a5a8e54f37099f and fixed in 6.18.40 with commit 5492799ec5d27be3bd454dcaf046bc7054f637ae
	Issue introduced in 5.8 with commit 8230fd8217b7ea76f838ae88e4a5a8e54f37099f and fixed in 7.1.5 with commit e3e59ff22a0de01ed0cf3a3e25558811abc3b70a
	Issue introduced in 5.8 with commit 8230fd8217b7ea76f838ae88e4a5a8e54f37099f and fixed in 7.2-rc2 with commit 794a01110390c1b76f59ece773fb0fbfd89c6f5c

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-72373
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/afs/callback.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/a99a617701186dc68c7b330d35fc2253f48e2ab2
	https://git.kernel.org/stable/c/5492799ec5d27be3bd454dcaf046bc7054f637ae
	https://git.kernel.org/stable/c/e3e59ff22a0de01ed0cf3a3e25558811abc3b70a
	https://git.kernel.org/stable/c/794a01110390c1b76f59ece773fb0fbfd89c6f5c