CVE-2026-31518: Linux kernel · esp: fix skb leak with espintcp and async crypto
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in df6f995358dc1f3c42484f5cfe241d7bd3e1cd15 : update Linux kernel when convenient.
Data as of 5 Nov 2026, 22:17 UTC
Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- 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, 2026-11-05.
- Patch
- Available – fixed in df6f995358dc1f3c42484f5cfe241d7bd3e1cd15, aca3ad0c262f54a5b5c95dda80a48365997d1224, 4820847e036ff1035b01b69ad68dfc17e7028fe9 +5
Exploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 5 Nov 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 has been implemented in the Linux kernel source code to address this issue. Users should update to the fixed versions identified by the commit hashes provided by the Linux project. Since this is a kernel-level fix, applying the official kernel updates that include these commits will remediate the vulnerability.
Description
A vulnerability in the Linux kernel's ESP implementation caused a socket buffer (skb) memory leak when using espintcp with asynchronous cryptography. This occurred because the skb was not freed when the TX queue was full and esp_output_tail_tcp returned an error. The issue has been fixed by ensuring the skb is dropped properly in the async crypto path.
References
- git.kernel.org/stable/c/aca3ad0c262f54a5b5c95dda80a48365997d1224 (opens in a new tab)
- git.kernel.org/stable/c/41aafca57de4a4c026701622bd4648f112a9edcd (opens in a new tab)
- git.kernel.org/stable/c/4820847e036ff1035b01b69ad68dfc17e7028fe9 (opens in a new tab)
- git.kernel.org/stable/c/6a3ec6efbc4f90e0ccb2e71574f07351f19996f4 (opens in a new tab)
- git.kernel.org/stable/c/df6f995358dc1f3c42484f5cfe241d7bd3e1cd15 (opens in a new tab)
- git.kernel.org/stable/c/88d386243ed374ac969dabd3bbc1409a31d81818 (opens in a new tab)
- git.kernel.org/stable/c/6aa9841d917532d0f2d932d1ff2f3a94305aaf47 (opens in a new tab)
- git.kernel.org/stable/c/0c0eef8ccd2413b0a10eb6bbd3442333b1e64dd2 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (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)