CVE-2026-31696

Advisory lineage Upstream: 0 Downstream: 5
Modified
Published: 01 May 2026, 13:55
Last modified:01 Jun 2026, 16:13

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (nvd)
EPSS Score
0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

01 May 2026, 13:55
Published
Vulnerability first disclosed
01 Jun 2026, 16:13
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 4%

Techniques & Countermeasures

  • CWE-787•Out-of-bounds Write

    The product writes data past the end, or before the beginning, of the intended buffer.

Affected Systems

  • linux•linux

    ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 44714dfda386884919ba366411880b6fb3c3efd3 | ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 41a117dd80371343babc52198d1114e83eb37627 | ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 9a397aa9b5e53ca63d4d6aefb542832eca389618 | ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 1fa36cf495b0023e8475d038535c05e4063211e1 | ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < 4458757c020592a3094366e0fb20457383b42f92 | ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < ce383ba615339f8eaec646a166d2c2b015bb5ca0 | ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < a1be1c9ece26cea69654f28b255ff9a7906b897b | ≥ 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247, < ac33733b10b484d666f97688561670afd5861383 | 3.17

  • linux•linux_kernel

    ≥ 3.17, < 6.6.136 | ≥ 6.7, < 6.12.84 | ≥ 6.13, < 6.18.25 | ≥ 6.19, < 7.0.2 | 7.1:rc1 | 7.1:rc2

References (8)