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VulnerabilityPublished Updated

CVE-2025-40135: Linux kernel · ipv6: use RCU in ip6_xmit()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · CVSS 8.1 High · fixed in f69fec6287565fdeb61f65e700a1184352306943 : patch Linux kernel soon.

Data as of 30 Oct 2026, 12:49 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.18.1
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-06-16.

Patch
Available – fixed in f69fec6287565fdeb61f65e700a1184352306943, f7f9e924f23684b4b23cd9f976cceab24a968e34, f0a54d00d2f36de40266f47c27989853e8588656 +3
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Nov 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, < f69fec6287565fdeb61f65e700a1184352306943
Fixed in
  • f69fec6287565fdeb61f65e700a1184352306943
LinuxLinuxAffected
  • ≥ 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, < f7f9e924f23684b4b23cd9f976cceab24a968e34
Fixed in
  • f7f9e924f23684b4b23cd9f976cceab24a968e34
LinuxLinuxAffected
  • ≥ 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, < f0a54d00d2f36de40266f47c27989853e8588656
Fixed in
  • f0a54d00d2f36de40266f47c27989853e8588656
LinuxLinuxAffected
  • ≥ 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, < bd0905e2122e3680968cd0741966983490bf2ed3
Fixed in
  • bd0905e2122e3680968cd0741966983490bf2ed3
LinuxLinuxAffected
  • ≥ 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, < 9085e56501d93af9f2d7bd16f7fcfacdde47b99c
Fixed in
  • 9085e56501d93af9f2d7bd16f7fcfacdde47b99c
LinuxLinuxAffected
  • ≥ 4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36, < 7a228cfbb66cca49e9baf901c506364f8dfe036b
Fixed in
  • 7a228cfbb66cca49e9baf901c506364f8dfe036b

AI-suggested

A fix is available and has been applied in the Linux kernel source code as indicated by multiple commit hashes. Users and administrators should update affected Linux kernel versions to the patched releases that include these fixes. Since this is a kernel-level vulnerability, applying the official kernel updates is the recommended remediation.

Description

CVE-2025-40135 is a high severity vulnerability in the Linux kernel's IPv6 implementation. It involves improper use of reference counting in the ip6_xmit() function, which could lead to a use-after-free (UAF) condition. The issue was resolved by employing Read-Copy-Update (RCU) mechanisms to safely access network device structures. The vulnerability affects Linux kernel version 4.13. A fix has been committed in multiple patches identified by their commit hashes.

References

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