---
id: CVE-2024-26689
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ceph: prevent use-after-free in encode_cap_msg()

  In fs/ceph/caps.c, in encode_cap_msg(), "use after free" error was
  caught by KASAN at this line - 'ceph_buffer_get(arg…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ceph: prevent use-after-free in encode_cap_msg()

  In fs/ceph/caps.c, in encode_cap_msg(), "use after free" error was
  caught by KASAN at this line - 'ceph_buffer_get(arg…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
vendor: linux
product: linux_kernel
affected:
  - linux_kernel < 5.10.210
  - 'linux_kernel >= 5.11, < 5.15.149'
  - 'linux_kernel >= 5.16, < 6.1.79'
  - 'linux_kernel >= 6.2, < 6.6.18'
  - 'linux_kernel >= 6.7, < 6.7.6'
  - linux_kernel = 6.8
  - debian_linux = 10.0
patched:
  - linux_kernel 6.7.6
published: '2024-04-03'
updated: '2026-08-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2024-26689'
references:
  - url: 'https://git.kernel.org/stable/c/70e329b440762390258a6fe8c0de93c9fdd56c77'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7958c1bf5b03c6f1f58e724dbdec93f8f60b96fc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8180d0c27b93a6eb60da1b08ea079e3926328214'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ae20db45e482303a20e56f2db667a9d9c54ac7e7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cda4672da1c26835dcbd7aec2bfed954eda9b5ef'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f3f98d7d84b31828004545e29fd7262b9f444139'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/70e329b440762390258a6fe8c0de93c9fdd56c77'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/7958c1bf5b03c6f1f58e724dbdec93f8f60b96fc'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/8180d0c27b93a6eb60da1b08ea079e3926328214'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/ae20db45e482303a20e56f2db667a9d9c54ac7e7'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/cda4672da1c26835dcbd7aec2bfed954eda9b5ef'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/f3f98d7d84b31828004545e29fd7262b9f444139'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00696
epssPercentile: 0.50914
ingestedAt: '2026-08-05T10:46:47.957Z'
---

## Overview

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

ceph: prevent use-after-free in encode_cap_msg()

In fs/ceph/caps.c, in encode_cap_msg(), "use after free" error was
caught by KASAN at this line - 'ceph_buffer_get(arg->xattr_buf);'. This
implies before the refcount could be increment here, it was freed.

In same file, in "handle_cap_grant()" refcount is decremented by this
line - 'ceph_buffer_put(ci->i_xattrs.blob);'. It appears that a race
occurred and resource was freed by the latter line before the former
line could increment it.

encode_cap_msg() is called by __send_cap() and __send_cap() is called by
ceph_check_caps() after calling __prep_cap(). __prep_cap() is where
arg->xattr_buf is assigned to ci->i_xattrs.blob. This is the spot where
the refcount must be increased to prevent "use after free" error.

## Affected

- `linux_kernel < 5.10.210`
- `linux_kernel >= 5.11, < 5.15.149`
- `linux_kernel >= 5.16, < 6.1.79`
- `linux_kernel >= 6.2, < 6.6.18`
- `linux_kernel >= 6.7, < 6.7.6`
- `linux_kernel = 6.8`
- `debian_linux = 10.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.7.6`