High 7.8Published May 1, 2026

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

Updated under an hour ago (Oct 28, 2026, 2:00 AM ET)

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Exploited in the last 30 days

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.

CVSS: 7.8 HIGH (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 before 44714dfda386884919ba366411880b6fb3c3efd3; from 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 before 41a117dd80371343babc52198d1114e83eb37627; from 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 before 9a397aa9b5e53ca63d4d6aefb542832eca389618; 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 builds before 1fa36cf495b0023e8475d038535c05e4063211e1; from 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 before 4458757c020592a3094366e0fb20457383b42f92; from 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 before ce383ba615339f8eaec646a166d2c2b015bb5ca0; from 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 before a1be1c9ece26cea69654f28b255ff9a7906b897b; from 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 before ac33733b10b484d666f97688561670afd5861383	CNA record
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
linux linux_kernel linux:linux_kernel	from 3.17 before 6.6.136; from 6.7 before 6.12.84; from 6.13 before 6.18.25; from 6.19 before 7.0.2; 7.1; 7.1	NVD

References

References

https://git.kernel.org/stable/c/44714dfda386884919ba366411880b6fb3c3efd3
https://git.kernel.org/stable/c/41a117dd80371343babc52198d1114e83eb37627
https://git.kernel.org/stable/c/9a397aa9b5e53ca63d4d6aefb542832eca389618
https://git.kernel.org/stable/c/1fa36cf495b0023e8475d038535c05e4063211e1	patch
https://git.kernel.org/stable/c/4458757c020592a3094366e0fb20457383b42f92	patch
https://git.kernel.org/stable/c/ce383ba615339f8eaec646a166d2c2b015bb5ca0	patch
https://git.kernel.org/stable/c/a1be1c9ece26cea69654f28b255ff9a7906b897b	patch
https://git.kernel.org/stable/c/ac33733b10b484d666f97688561670afd5861383	patch
https://cert-portal.siemens.com/productcert/html/ssa-784472.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.