VulnerabilityPublished 1 May 2026Updated 6 Nov 2026

CVE-2026-31696: Linux kernel · rxrpc: Fix missing validation of ticket length in non-XDR key preparsing

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in ce383ba615339f8eaec646a166d2c2b015bb5ca0 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 15:49 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

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, 2026-11-06.

Patch

Available – fixed in ce383ba615339f8eaec646a166d2c2b015bb5ca0, ac33733b10b484d666f97688561670afd5861383, a1be1c9ece26cea69654f28b255ff9a7906b897b +5

Exploitation evidence

Disclosed: evidence found.
CVE published 1 May 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 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < ce383ba615339f8eaec646a166d2c2b015bb5ca0	Fixed in ce383ba615339f8eaec646a166d2c2b015bb5ca0
LinuxLinux	Affected ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < ac33733b10b484d666f97688561670afd5861383	Fixed in ac33733b10b484d666f97688561670afd5861383
LinuxLinux	Affected ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < a1be1c9ece26cea69654f28b255ff9a7906b897b	Fixed in a1be1c9ece26cea69654f28b255ff9a7906b897b
LinuxLinux	Affected ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 4458757c020592a3094366e0fb20457383b42f92	Fixed in 4458757c020592a3094366e0fb20457383b42f92
LinuxLinux	Affected ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 44714dfda386884919ba366411880b6fb3c3efd3	Fixed in 44714dfda386884919ba366411880b6fb3c3efd3
LinuxLinux	Affected ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 41a117dd80371343babc52198d1114e83eb37627	Fixed in 41a117dd80371343babc52198d1114e83eb37627

Description

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix missing validation of ticket length in non-XDR key preparsing In rxrpc_preparse(), there are two paths for parsing key payloads: the XDR path (for large payloads) and the non-XDR path (for payloads <= 28 bytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly validates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR path fails to do so. This allows an unprivileged user to provide a very large ticket length. When this key is later read via rxrpc_read(), the total token size (toksize) calculation results in a value that exceeds AFSTOKEN_LENGTH_MAX, triggering a WARN_ON(). [ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc] Fix this by adding a check in the non-XDR parsing path of rxrpc_preparse() to ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX, bringing it into parity with the XDR parsing logic.

References

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