---
id: CVE-2026-43304
title: 'libceph: define and enforce CEPH_MAX_KEY_LEN'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  libceph: define and enforce CEPH_MAX_KEY_LEN

  When decoding the key, verify that the key material would fit into
  a fixed-size buffer in process_auth_done() and generall…
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    6405e8c680974bb74e2c98d5249fb52c7b12a6c6
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    8d745d38c88ecbed95f6b2b39857bf89f35a3244
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    e1dc45d97975f9db65694d234fbddf1915176e16
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    1b275bd49e58752efb83767a5d1aed41356c5e64
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    c1a0f5f1e5e7e98c36a362ec3d1fcfd9932931ed
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    d82467c07b03a27c3c5469b62bb3b726305a80bb
  - >-
    Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 <
    ac431d597a9bdfc2ba6b314813f29a6ef2b4a3bf
  - Linux 5.11
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T15:16:20.550708Z'
published: '2026-05-08'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:38.629Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43304'
references:
  - url: 'https://git.kernel.org/stable/c/6405e8c680974bb74e2c98d5249fb52c7b12a6c6'
  - url: 'https://git.kernel.org/stable/c/8d745d38c88ecbed95f6b2b39857bf89f35a3244'
  - url: 'https://git.kernel.org/stable/c/e1dc45d97975f9db65694d234fbddf1915176e16'
  - url: 'https://git.kernel.org/stable/c/1b275bd49e58752efb83767a5d1aed41356c5e64'
  - url: 'https://git.kernel.org/stable/c/c1a0f5f1e5e7e98c36a362ec3d1fcfd9932931ed'
  - url: 'https://git.kernel.org/stable/c/d82467c07b03a27c3c5469b62bb3b726305a80bb'
  - url: 'https://git.kernel.org/stable/c/ac431d597a9bdfc2ba6b314813f29a6ef2b4a3bf'
tags:
  - cve.org
epss: 0.00738
epssPercentile: 0.53607
ingestedAt: '2026-10-16T17:24:46.691Z'
---

## Overview

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

libceph: define and enforce CEPH_MAX_KEY_LEN

When decoding the key, verify that the key material would fit into
a fixed-size buffer in process_auth_done() and generally has a sane
length.

The new CEPH_MAX_KEY_LEN check replaces the existing check for a key
with no key material which is a) not universal since CEPH_CRYPTO_NONE
has to be excluded and b) doesn't provide much value since a smaller
than needed key is just as invalid as no key -- this has to be handled
elsewhere anyway.

## Affected

- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < 6405e8c680974bb74e2c98d5249fb52c7b12a6c6`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < 8d745d38c88ecbed95f6b2b39857bf89f35a3244`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < e1dc45d97975f9db65694d234fbddf1915176e16`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < 1b275bd49e58752efb83767a5d1aed41356c5e64`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < c1a0f5f1e5e7e98c36a362ec3d1fcfd9932931ed`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < d82467c07b03a27c3c5469b62bb3b726305a80bb`
- `Linux >= cd1a677cad994021b19665ed476aea63f5d54f31 < ac431d597a9bdfc2ba6b314813f29a6ef2b4a3bf`
- `Linux 5.11`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.