CVE-2026-89954: mtd: afs: validate v2 image info bounds

CVE-2026-89954: mtd: afs: validate v2 image info bounds

[Greg Kroah-Hartman]

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

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

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

mtd: afs: validate v2 image info bounds

The AFS v2 parser uses footer[8] to locate the image information block
inside the current erase block, then uses the image information
region_count to walk entries from a fixed local array. The footer offset
and region count come from flash contents and are not checked against the
erase block or the local image-info array before use.

Reject v2 entries whose image information offset would underflow the
erase block calculation, and reject region counts that cannot fit in the
local image-info array before walking region entries.

The Linux kernel CVE team has assigned CVE-2026-89954 to this issue.


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

	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 5.10.270 with commit 1bec05a68414cf8d0cab6cb42445b8603f32ffc4
	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 5.15.221 with commit 3ad8ff12fd44b08af9212ac4883a7e29d2ab7348
	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 6.1.188 with commit 875daa3c750814ff2e2dc050239c390048f0bcd0
	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 6.6.157 with commit da740539e8f370767317e24615349b9342a6e773
	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 6.12.110 with commit 1edea8900ca3e405c1421d8b5c29f97107874f72
	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 6.18.51 with commit 18916f475057cbd2fb8ea6ae86e6b85884ad1d53
	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 7.2.5 with commit d14e6298139f58a87a87d7022e26a7f37f0ddce7
	Issue introduced in 5.2 with commit b7cf5e2830bbb128699d7635ce8404b7f605bc95 and fixed in 7.3-rc1 with commit e9290031f736e99ad17c25c00311c92c266843b7

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-2026-89954
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:
	drivers/mtd/parsers/afs.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/1bec05a68414cf8d0cab6cb42445b8603f32ffc4
	https://git.kernel.org/stable/c/3ad8ff12fd44b08af9212ac4883a7e29d2ab7348
	https://git.kernel.org/stable/c/875daa3c750814ff2e2dc050239c390048f0bcd0
	https://git.kernel.org/stable/c/da740539e8f370767317e24615349b9342a6e773
	https://git.kernel.org/stable/c/1edea8900ca3e405c1421d8b5c29f97107874f72
	https://git.kernel.org/stable/c/18916f475057cbd2fb8ea6ae86e6b85884ad1d53
	https://git.kernel.org/stable/c/d14e6298139f58a87a87d7022e26a7f37f0ddce7
	https://git.kernel.org/stable/c/e9290031f736e99ad17c25c00311c92c266843b7