---
id: CVE-2026-80536
title: 'xfs: bounds-check buffer log item''s dirty bitmap'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xfs: bounds-check buffer log item's dirty bitmap

  xlog_recover_do_reg_buffer() replays each dirty region described by a
  buffer log item's bitmap into the buffer read fo…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    acb4e26295e7f0e685815a3fd3d70bd8329cefa1
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    f3859c35a4fbc1c1c58431f684f808e43696891d
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    f7b5fa83e2c192be922121b764415fa8c7549ea1
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    b7528b42813f02724a78fce1da24d69d1bfc4d38
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    7e32d4eebae6ca24f8a673c107fd7eca1f47afc2
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    f8288214459ead7e87d26e5822f62c14a4f2ed6b
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    edaf5b6bd625356893da20d69a259b34a9de2694
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    813f8136a2ce1fee266d02a7df73db6e8a541604
  - Linux 2.6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T19:16:45.666700Z'
published: '2026-08-26'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:26:25.114Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80536'
references:
  - url: 'https://git.kernel.org/stable/c/acb4e26295e7f0e685815a3fd3d70bd8329cefa1'
  - url: 'https://git.kernel.org/stable/c/f3859c35a4fbc1c1c58431f684f808e43696891d'
  - url: 'https://git.kernel.org/stable/c/f7b5fa83e2c192be922121b764415fa8c7549ea1'
  - url: 'https://git.kernel.org/stable/c/b7528b42813f02724a78fce1da24d69d1bfc4d38'
  - url: 'https://git.kernel.org/stable/c/7e32d4eebae6ca24f8a673c107fd7eca1f47afc2'
  - url: 'https://git.kernel.org/stable/c/f8288214459ead7e87d26e5822f62c14a4f2ed6b'
  - url: 'https://git.kernel.org/stable/c/edaf5b6bd625356893da20d69a259b34a9de2694'
  - url: 'https://git.kernel.org/stable/c/813f8136a2ce1fee266d02a7df73db6e8a541604'
tags:
  - cve.org
epss: 0.00142
epssPercentile: 0.03114
ingestedAt: '2026-10-16T19:46:24.320Z'
---

## Overview

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

xfs: bounds-check buffer log item's dirty bitmap

xlog_recover_do_reg_buffer() replays each dirty region described by a
buffer log item's bitmap into the buffer read for that item:

	memcpy(xfs_buf_offset(bp, (uint)bit << XFS_BLF_SHIFT),
		item->ri_buf[i].iov_base,
		nbits << XFS_BLF_SHIFT);

The destination offset (bit/nbits, from the logged dirty bitmap) and the
buffer size (from the logged blf_len) are both attacker-controlled and
otherwise unrelated, yet the only thing bounding the copy is an ASSERT(),
which compiles away on production kernels. A crafted image logging a
small blf_len together with a bitmap bit past the end of that buffer
drives the memcpy() past the buffer's allocation, corrupting adjacent
kernel heap during mount-time log recovery. This is reachable by anyone
who can get a crafted image mounted -- the malicious-filesystem threat
model XFS already guards against elsewhere.

Turn the ASSERT() into a real XFS_IS_CORRUPT() check that aborts recovery
of the buffer with -EFSCORRUPTED, consistent with the validate-and-fail
idiom already used in xlog_recover_do_inode_buffer() and
xfs_dquot_item_recover.c. xlog_recover_do_reg_buffer() therefore becomes
STATIC int and its three callers propagate the error.

Found and confirmed with KASAN on a CONFIG_XFS_DEBUG=n build: the crafted
image trips a slab-out-of-bounds write before this change and fails
recovery cleanly with -EFSCORRUPTED after it.

## Affected

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < acb4e26295e7f0e685815a3fd3d70bd8329cefa1`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f3859c35a4fbc1c1c58431f684f808e43696891d`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f7b5fa83e2c192be922121b764415fa8c7549ea1`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b7528b42813f02724a78fce1da24d69d1bfc4d38`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7e32d4eebae6ca24f8a673c107fd7eca1f47afc2`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f8288214459ead7e87d26e5822f62c14a4f2ed6b`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < edaf5b6bd625356893da20d69a259b34a9de2694`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 813f8136a2ce1fee266d02a7df73db6e8a541604`
- `Linux 2.6.12`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.