---
id: CVE-2026-52914
title: 'batman-adv: fix fragment reassembly length accounting'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  batman-adv: fix fragment reassembly length accounting

  batman-adv keeps a running payload length for queued fragments and uses it
  to validate a fragment chain before re…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    e4f3f6b818aa6a678bc54a2d4e0bece2303c6a64
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    37be61825b15534a16ff9cfc9546de155b6df982
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    975563c5de1123dde1ec7946bf5556d20c89d74e
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    f653b040dad1af70fa5cd4fe085e4758925480c9
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    e910dbf509125fe51ad68e4fa74dc8ab0a8e787a
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    3eb8bcb823391bd58997831b3c9c152a4ba8e255
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    fdb2c96efb2baeb3725e9ce3ede8f1e36f5490f0
  - >-
    Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 <
    9cd3f16c320bfdadd4509358122368deb56a5741
  - Linux 3.13
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T15:22:33.098650Z'
published: '2026-06-24'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:31:18.442Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-52914'
references:
  - url: 'https://git.kernel.org/stable/c/e4f3f6b818aa6a678bc54a2d4e0bece2303c6a64'
  - url: 'https://git.kernel.org/stable/c/37be61825b15534a16ff9cfc9546de155b6df982'
  - url: 'https://git.kernel.org/stable/c/975563c5de1123dde1ec7946bf5556d20c89d74e'
  - url: 'https://git.kernel.org/stable/c/f653b040dad1af70fa5cd4fe085e4758925480c9'
  - url: 'https://git.kernel.org/stable/c/e910dbf509125fe51ad68e4fa74dc8ab0a8e787a'
  - url: 'https://git.kernel.org/stable/c/3eb8bcb823391bd58997831b3c9c152a4ba8e255'
  - url: 'https://git.kernel.org/stable/c/fdb2c96efb2baeb3725e9ce3ede8f1e36f5490f0'
  - url: 'https://git.kernel.org/stable/c/9cd3f16c320bfdadd4509358122368deb56a5741'
tags:
  - cve.org
epss: 0.00513
epssPercentile: 0.42405
ingestedAt: '2026-10-16T17:24:46.718Z'
---

## Overview

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

batman-adv: fix fragment reassembly length accounting

batman-adv keeps a running payload length for queued fragments and uses it
to validate a fragment chain before reassembly.

That accounting currently allows the accumulated fragment length to be
truncated during updates. As a result, malformed fragment chains can
bypass the intended validation and drive reassembly with inconsistent
length state, leading to a local denial of service.

Fix the accounting by storing the accumulated length in a length-typed
field and rejecting update overflows before the existing validation logic
runs.

The fix was verified against the original reproducer and against valid
fragment reassembly paths.

## Affected

- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < e4f3f6b818aa6a678bc54a2d4e0bece2303c6a64`
- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < 37be61825b15534a16ff9cfc9546de155b6df982`
- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < 975563c5de1123dde1ec7946bf5556d20c89d74e`
- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < f653b040dad1af70fa5cd4fe085e4758925480c9`
- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < e910dbf509125fe51ad68e4fa74dc8ab0a8e787a`
- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < 3eb8bcb823391bd58997831b3c9c152a4ba8e255`
- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < fdb2c96efb2baeb3725e9ce3ede8f1e36f5490f0`
- `Linux >= 610bfc6bc99bc83680d190ebc69359a05fc7f605 < 9cd3f16c320bfdadd4509358122368deb56a5741`
- `Linux 3.13`

## Remediation

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