From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-90279: md/raid5: round bitmap stripes with sector division
Date: Thu, 17 Sep 2026 17:11:49 +0100 [thread overview]
Message-ID: <2026091750-CVE-2026-90279-85bb@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
md/raid5: round bitmap stripes with sector division
raid5_bitmap_sector_map() aligns the array range to full RAID5 stripe
widths before converting it to component sectors. That width is
chunk_sectors multiplied by the number of data disks, and it is not
always a power of two.
Reproduce with a 4-disk RAID5, 1024-sector chunks, and three data disks.
The full-stripe width is 3072 sectors. For a one-sector write at array
sector 3072, correct rounding gives array range [3072, 6144), which maps
to component range [1024, 2048). The old round_down()/round_up() logic
instead gives [1024, 4096), which maps to [0, 1024).
Use sector_div() based arithmetic so the rounded range is aligned to the
actual RAID5 stripe width.
The deterministic mapper test now reports the fixed component range as
[1024, 2048), while the old mask-based range was [0, 1024).
The Linux kernel CVE team has assigned CVE-2026-90279 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.6.79 with commit b29e6400be51c214a0ad30dce937348b57abe33a and fixed in 6.6.157 with commit 9d7490007707f90691911385365bd1d691d99225
Issue introduced in 6.12.13 with commit aa8e15d69f5c0044d5bff61844e163aacc4ac172 and fixed in 6.12.110 with commit cab7d949b18b2f1cd625689dc16c5f81236bac93
Issue introduced in 6.14 with commit 9c89f604476cf15c31fbbdb043cff7fbf1dbe0cb and fixed in 6.18.52 with commit 02c10581866d08822c6348e299881485fc546185
Issue introduced in 6.14 with commit 9c89f604476cf15c31fbbdb043cff7fbf1dbe0cb and fixed in 7.2.6 with commit ccbdc483eb041eef809e9ff223d1ad63518a2c52
Issue introduced in 6.14 with commit 9c89f604476cf15c31fbbdb043cff7fbf1dbe0cb and fixed in 7.3-rc1 with commit 17ea021ae74987d6064c8195c4922fa025753892
Issue introduced in 6.13.2 with commit a41a0df5d7638acf15e723ad985980b4f7ff9383
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-2026-90279
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/md/raid5.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/9d7490007707f90691911385365bd1d691d99225
https://git.kernel.org/stable/c/cab7d949b18b2f1cd625689dc16c5f81236bac93
https://git.kernel.org/stable/c/02c10581866d08822c6348e299881485fc546185
https://git.kernel.org/stable/c/ccbdc483eb041eef809e9ff223d1ad63518a2c52
https://git.kernel.org/stable/c/17ea021ae74987d6064c8195c4922fa025753892
reply other threads:[~2026-09-17 16:23 UTC|newest]
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