CVE-2026-80669: bpf: Disable xfrm_decode_session hook attachment

CVE-2026-80669: bpf: Disable xfrm_decode_session hook attachment

[Greg Kroah-Hartman]

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

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

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

bpf: Disable xfrm_decode_session hook attachment

BPF LSM programs can currently attach to xfrm_decode_session(). That
hook may return an error, but security_skb_classify_flow() calls it
from a void path and triggers BUG_ON() if an error is returned.

Disable BPF attachment to the hook to prevent a BPF LSM program from
turning packet classification into a full panic.

The Linux kernel CVE team has assigned CVE-2026-80669 to this issue.


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

	Issue introduced in 5.7 with commit 9e4e01dfd3254c7f04f24b7c6b29596bc12332f3 and fixed in 6.1.178 with commit aa265d47308775c5501073b08133623bcb5421f9
	Issue introduced in 5.7 with commit 9e4e01dfd3254c7f04f24b7c6b29596bc12332f3 and fixed in 6.6.145 with commit 6b44c6660aa1c9b843e450a623ac4a8484919dce
	Issue introduced in 5.7 with commit 9e4e01dfd3254c7f04f24b7c6b29596bc12332f3 and fixed in 6.12.97 with commit 4ae780d173ef40d4f7cb76935dc2d55fbf380009
	Issue introduced in 5.7 with commit 9e4e01dfd3254c7f04f24b7c6b29596bc12332f3 and fixed in 6.18.40 with commit 49fa1be621dde8f526d36e5791aded8fafda1e9c
	Issue introduced in 5.7 with commit 9e4e01dfd3254c7f04f24b7c6b29596bc12332f3 and fixed in 7.1.5 with commit 1bb3b6a5c3c5cc814eae4ff0212fdced36f8bce9
	Issue introduced in 5.7 with commit 9e4e01dfd3254c7f04f24b7c6b29596bc12332f3 and fixed in 7.2 with commit 12091470c6b4c1c14b2de12dcbae2ada6cb6d20b

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-2026-80669
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:
	kernel/bpf/bpf_lsm.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/aa265d47308775c5501073b08133623bcb5421f9
	https://git.kernel.org/stable/c/6b44c6660aa1c9b843e450a623ac4a8484919dce
	https://git.kernel.org/stable/c/4ae780d173ef40d4f7cb76935dc2d55fbf380009
	https://git.kernel.org/stable/c/49fa1be621dde8f526d36e5791aded8fafda1e9c
	https://git.kernel.org/stable/c/1bb3b6a5c3c5cc814eae4ff0212fdced36f8bce9
	https://git.kernel.org/stable/c/12091470c6b4c1c14b2de12dcbae2ada6cb6d20b