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VulnerabilityPublished Updated

CVE-2025-71085: Linux kernel · ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.5 High · fixed in c53aa6a5086f03f19564096ee084a202a8c738c0 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 23% 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 cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-06-10.

Patch
Available – fixed in c53aa6a5086f03f19564096ee084a202a8c738c0, bf3709738d8a8cc6fa275773170c5c29511a0b24, 73744ad5696dce0e0f43872aba8de6a83d6ad570 +4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Jan 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
  • ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < c53aa6a5086f03f19564096ee084a202a8c738c0
Fixed in
  • c53aa6a5086f03f19564096ee084a202a8c738c0
LinuxLinuxAffected
  • ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < bf3709738d8a8cc6fa275773170c5c29511a0b24
Fixed in
  • bf3709738d8a8cc6fa275773170c5c29511a0b24
LinuxLinuxAffected
  • ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 73744ad5696dce0e0f43872aba8de6a83d6ad570
Fixed in
  • 73744ad5696dce0e0f43872aba8de6a83d6ad570
LinuxLinuxAffected
  • ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 86f365897068d09418488165a68b23cb5baa37f2
Fixed in
  • 86f365897068d09418488165a68b23cb5baa37f2
LinuxLinuxAffected
  • ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 58fc7342b529803d3c221101102fe913df7adb83
Fixed in
  • 58fc7342b529803d3c221101102fe913df7adb83
LinuxLinuxAffected
  • ≥ 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3, < 6b7522424529556c9cbc15e15e7bd4eeae310910
Fixed in
  • 6b7522424529556c9cbc15e15e7bd4eeae310910

AI-suggested

A fix is available and has been applied in multiple Linux kernel commits. Users should update their Linux kernel to a version including these fixes. No additional mitigation is required beyond applying the official patch. The vulnerability is not known to be exploited in the wild.

Description

CVE-2025-71085 is a high-severity vulnerability in the Linux kernel affecting IPv6 packet processing. It involves a kernel oops triggered by a BUG_ON condition in the pskb_expand_head() function due to an integer cast error in skb_cow() when handling large headroom values. This flaw can cause a denial of service by crashing the kernel. The issue is fixed by correcting the condition in calipso_skbuff_setattr() to prevent passing negative headroom sizes. The vulnerability affects Linux kernel version 4.8 and has been patched in subsequent commits.

References

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