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CVE-2026-31696

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.84, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in 44714dfda386884919ba366411880b6fb3c3efd3; From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in 41a117dd80371343babc52198d1114e83eb37627; From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in 9a397aa9b5e53ca63d4d6aefb542832eca389618; From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in 1fa36cf495b0023e8475d038535c05e4063211e1; From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in 4458757c020592a3094366e0fb20457383b42f92; From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in ce383ba615339f8eaec646a166d2c2b015bb5ca0; From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in a1be1c9ece26cea69654f28b255ff9a7906b897b; From 8a7a3eb4ddbe7c7e639170a64adede7cbd5a9247 · fixed in ac33733b10b484d666f97688561670afd5861383

  • Linux Linux

    3.17

  • KernelLinux

    From 3.17.0 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.136; From 6.7.0 · fixed in 6.12.84; From 6.13.0 · fixed in 6.18.25; From 6.19.0 · fixed in 7.0.2

References 8

git.kernel.org