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VulnerabilityPublished Updated

CVE-2026-31659: Linux kernel · batman-adv: reject oversized global TT response buffers

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in f970646b9a39539d1bac86822ac78b5915455ea9 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f970646b9a39539d1bac86822ac78b5915455ea9, de6c1dc3c7d01a152607e6fcecee4d5288283f10, cf2199171ef799ca7270019125f4a91bd20ad4d9 +5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b, < f970646b9a39539d1bac86822ac78b5915455ea9
Fixed in
  • f970646b9a39539d1bac86822ac78b5915455ea9
LinuxLinuxAffected
  • ≥ 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b, < de6c1dc3c7d01a152607e6fcecee4d5288283f10
Fixed in
  • de6c1dc3c7d01a152607e6fcecee4d5288283f10
LinuxLinuxAffected
  • ≥ 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b, < cf2199171ef799ca7270019125f4a91bd20ad4d9
Fixed in
  • cf2199171ef799ca7270019125f4a91bd20ad4d9
LinuxLinuxAffected
  • ≥ 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b, < 2997f4bd1f982e7013709946e00be89b507693fa
Fixed in
  • 2997f4bd1f982e7013709946e00be89b507693fa
LinuxLinuxAffected
  • ≥ 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b, < 95c71365a2222908441b54d6f2c315e0c79fcec3
Fixed in
  • 95c71365a2222908441b54d6f2c315e0c79fcec3
LinuxLinuxAffected
  • ≥ 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b, < 69d61639bc7e963c3b645e570279d731e7c89062
Fixed in
  • 69d61639bc7e963c3b645e570279d731e7c89062

AI-suggested

A fix is available in the Linux kernel as indicated by multiple fixed commit versions. Users should update to a Linux kernel version that includes these fixes. Since this is not a cloud service, manual patching is required. No alternative mitigations are specified.

Description

CVE-2026-31659 is a critical vulnerability in the Linux kernel's batman-adv module where oversized global TT response buffers are not properly rejected. This flaw allows a heap buffer overflow due to a 16-bit length field wrapping, causing memory corruption before a packet-size check occurs. The issue is fixed by rejecting TT responses with TVLV payload lengths that exceed the 16-bit limit.

References

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