CVE-2026-31659: Linux kernel · batman-adv: reject oversized global TT response buffers
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/7e5d007e0df946bffb8542fb112e0044014a5897 (opens in a new tab)
- git.kernel.org/stable/c/2997f4bd1f982e7013709946e00be89b507693fa (opens in a new tab)
- git.kernel.org/stable/c/95c71365a2222908441b54d6f2c315e0c79fcec3 (opens in a new tab)
- git.kernel.org/stable/c/69d61639bc7e963c3b645e570279d731e7c89062 (opens in a new tab)
- git.kernel.org/stable/c/f970646b9a39539d1bac86822ac78b5915455ea9 (opens in a new tab)
- git.kernel.org/stable/c/de6c1dc3c7d01a152607e6fcecee4d5288283f10 (opens in a new tab)
- git.kernel.org/stable/c/cf2199171ef799ca7270019125f4a91bd20ad4d9 (opens in a new tab)
- git.kernel.org/stable/c/3a359bf5c61d52e7f09754108309d637532164a6 (opens in a new tab)