---
id: CVE-2026-31637
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  rxrpc: reject undecryptable rxkad response tickets

  rxkad_decrypt_ticket() decrypts the RXKAD response ticket and then
  parses the buffer as plaintext without checking w…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  rxrpc: reject undecryptable rxkad response tickets

  rxkad_decrypt_ticket() decrypts the RXKAD response ticket and then
  parses the buffer as plaintext without checking w…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 2.6.22.1, < 6.6.135'
  - 'linux_kernel >= 6.7, < 6.12.82'
  - 'linux_kernel >= 6.13, < 6.18.23'
  - 'linux_kernel >= 6.19, < 6.19.13'
  - linux_kernel = 2.6.22
  - linux_kernel = 7.0
patched:
  - linux_kernel 6.19.13
published: '2026-04-24'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:14.447'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31637'
references:
  - url: 'https://git.kernel.org/stable/c/22f6258e7b31dba9bf88dce4e3ee7f0f20072e60'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/252157d939d179b5d767cb860ff8fa7f8723b67a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/58fcd1b156152613ba00a064a129fb69507ddd7d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a149dcae23309df9de1c3b6b5d468610ef5ab7de'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a75b3b361dd481d942c5f259a82d59718a41092c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b3a808cd0790b5075aaa2bc3588edf02cd71d352'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fe4447cd95623b1cfacc15f280aab73a6d7340b2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00514
epssPercentile: 0.42369
ingestedAt: '2026-10-15T03:30:12.862Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

rxrpc: reject undecryptable rxkad response tickets

rxkad_decrypt_ticket() decrypts the RXKAD response ticket and then
parses the buffer as plaintext without checking whether
crypto_skcipher_decrypt() succeeded.

A malformed RESPONSE can therefore use a non-block-aligned ticket
length, make the decrypt operation fail, and still drive the ticket
parser with attacker-controlled bytes.

Check the decrypt result and abort the connection with RXKADBADTICKET
when ticket decryption fails.

## Affected

- `linux_kernel >= 2.6.22.1, < 6.6.135`
- `linux_kernel >= 6.7, < 6.12.82`
- `linux_kernel >= 6.13, < 6.18.23`
- `linux_kernel >= 6.19, < 6.19.13`
- `linux_kernel = 2.6.22`
- `linux_kernel = 7.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.13`