Improper input validation in Linux kernel - CVE-2026-31696
Published: May 2, 2026
Vulnerability identifier: #VU128997
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-31696
CWE-ID: CWE-20
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper input validation in rxrpc_preparse() when parsing non-XDR key payloads. A local user can provide a crafted key payload with an oversized ticket length to cause a denial of service.
The issue is triggered later when the key is read via rxrpc_read(), causing the token size calculation to exceed AFSTOKEN_LENGTH_MAX and hit a WARN_ON().
How to mitigate CVE-2026-31696
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/1fa36cf495b0023e8475d038535c05e4063211e1
- https://git.kernel.org/stable/c/4458757c020592a3094366e0fb20457383b42f92
- https://git.kernel.org/stable/c/a1be1c9ece26cea69654f28b255ff9a7906b897b
- https://git.kernel.org/stable/c/ac33733b10b484d666f97688561670afd5861383
- https://git.kernel.org/stable/c/ce383ba615339f8eaec646a166d2c2b015bb5ca0