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VulnerabilityPublished Updated

CVE-2026-31518: Linux kernel · esp: fix skb leak with espintcp and async crypto

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in df6f995358dc1f3c42484f5cfe241d7bd3e1cd15 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 22:17 UTC

Severity
Medium

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

  1. Disclosed: evidence found.

    CVE published 22 Apr 2026

  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 5 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < df6f995358dc1f3c42484f5cfe241d7bd3e1cd15
Fixed in
  • df6f995358dc1f3c42484f5cfe241d7bd3e1cd15
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < aca3ad0c262f54a5b5c95dda80a48365997d1224
Fixed in
  • aca3ad0c262f54a5b5c95dda80a48365997d1224
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < 4820847e036ff1035b01b69ad68dfc17e7028fe9
Fixed in
  • 4820847e036ff1035b01b69ad68dfc17e7028fe9
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < 88d386243ed374ac969dabd3bbc1409a31d81818
Fixed in
  • 88d386243ed374ac969dabd3bbc1409a31d81818
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < 41aafca57de4a4c026701622bd4648f112a9edcd
Fixed in
  • 41aafca57de4a4c026701622bd4648f112a9edcd
LinuxLinuxAffected
  • ≥ e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, < 6aa9841d917532d0f2d932d1ff2f3a94305aaf47
Fixed in
  • 6aa9841d917532d0f2d932d1ff2f3a94305aaf47

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

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