CVE-2026-90143: net: kcm: Hold RCU read lock while running BPF parser

CVE-2026-90143: net: kcm: Hold RCU read lock while running BPF parser

[Greg Kroah-Hartman]

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

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

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

net: kcm: Hold RCU read lock while running BPF parser

kcm_parse_func_strparser() calls bpf_prog_run_pin_on_cpu() which
prevents CPU migration, but does not establish an RCU read-side
critical section. Consequently, BPF map operations can trigger
WARN_ON_ONCE(!bpf_rcu_lock_held()) when called from the KCM strparser
program.

Hold the RCU read lock while running the program.

The Linux kernel CVE team has assigned CVE-2026-90143 to this issue.


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

	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 5.10.270 with commit 37108861cf7bd909d4a372069bcd61c8f489e232
	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 5.15.221 with commit 3c70d27e792a28bca650ddd8a9aa0fe3591ffec5
	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 6.1.188 with commit 1d26a6e007d46babc7fa76e5a157dccf86cd55c0
	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 6.6.157 with commit b0e94ea63dbdcbfec9beb819cd5f8fa584809ef2
	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 6.12.110 with commit 21526f8a191a3c50622b8c10bd927870d780eae4
	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 6.18.52 with commit 292846223eaddba890e40699d2ab82ee5671798c
	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 7.2.6 with commit f392affef3c9ce64dfdde794df0579e0a7793440
	Issue introduced in 4.9 with commit 9b73896a81dc68a638a011877b7344b252f92276 and fixed in 7.3-rc1 with commit b0346dd64e4905291cc9c479f2e6cf1884ced4e6

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-2026-90143
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:
	net/kcm/kcmsock.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/37108861cf7bd909d4a372069bcd61c8f489e232
	https://git.kernel.org/stable/c/3c70d27e792a28bca650ddd8a9aa0fe3591ffec5
	https://git.kernel.org/stable/c/1d26a6e007d46babc7fa76e5a157dccf86cd55c0
	https://git.kernel.org/stable/c/b0e94ea63dbdcbfec9beb819cd5f8fa584809ef2
	https://git.kernel.org/stable/c/21526f8a191a3c50622b8c10bd927870d780eae4
	https://git.kernel.org/stable/c/292846223eaddba890e40699d2ab82ee5671798c
	https://git.kernel.org/stable/c/f392affef3c9ce64dfdde794df0579e0a7793440
	https://git.kernel.org/stable/c/b0346dd64e4905291cc9c479f2e6cf1884ced4e6