CVE-2025-71085: Linux kernel · ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Jan 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 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
- git.kernel.org/stable/c/86f365897068d09418488165a68b23cb5baa37f2 (opens in a new tab)
- git.kernel.org/stable/c/6b7522424529556c9cbc15e15e7bd4eeae310910 (opens in a new tab)
- git.kernel.org/stable/c/2bb759062efa188ea5d07242a43e5aa5464bbae1 (opens in a new tab)
- git.kernel.org/stable/c/c53aa6a5086f03f19564096ee084a202a8c738c0 (opens in a new tab)
- git.kernel.org/stable/c/bf3709738d8a8cc6fa275773170c5c29511a0b24 (opens in a new tab)
- git.kernel.org/stable/c/73744ad5696dce0e0f43872aba8de6a83d6ad570 (opens in a new tab)
- git.kernel.org/stable/c/58fc7342b529803d3c221101102fe913df7adb83 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)