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VulnerabilityPublished Updated

CVE-2026-31640: Linux kernel · rxrpc: Fix use of wrong skb when comparing queued RESP challenge serial

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.5 High.

Data as of 12 Nov 2026, 03:19 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.17.5
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 24 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 11 Nov 2026.

What to do

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel. Users should apply the official kernel updates that include this patch to remediate the issue. Since this is a kernel-level fix, upgrading to the fixed kernel version is the recommended mitigation.

Description

A vulnerability in the Linux kernel's rxrpc subsystem was fixed where the code incorrectly compared the challenge serial number from a newer packet instead of the cached older response. This flaw caused the comparison to always fail, potentially leading to improper handling of response packets. The fix involves correcting the comparison to use the older packet and properly substituting the newer packet when appropriate.

References

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