---
id: CVE-2026-52955
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  libceph: Fix potential out-of-bounds access in crush_decode()

  A message of type CEPH_MSG_OSD_MAP containing a crush map with at least
  one bucket has two fields holding…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  libceph: Fix potential out-of-bounds access in crush_decode()

  A message of type CEPH_MSG_OSD_MAP containing a crush map with at least
  one bucket has two fields holding…
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'
published: '2026-06-24'
updated: '2026-06-29'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-52955'
references:
  - url: 'https://git.kernel.org/stable/c/0f3604cbe4df14c5e58288ac9f57511e726a222d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3f42508191e129ee6b5ea96578d5cab14f2a013a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4c79fc2d598694bda845b46229c9d48b65042970'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6e70ef53e818c53eab28d7b0026b7fd03dddaba5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cceb10023e76bc89f3fe9238ebd0ccab0fc7c7c5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ea0d42137f0c06da71e37ffc647aab4c5309599a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ebe76d58a48a48031b98543d86c4cd30a825b622'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fb176a99e4c1a5a8448a83d83d3606203ba81faa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00509
epssPercentile: 0.4094
ingestedAt: '2026-06-29T13:42:11.989Z'
---

## Overview

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

libceph: Fix potential out-of-bounds access in crush_decode()

A message of type CEPH_MSG_OSD_MAP containing a crush map with at least
one bucket has two fields holding the bucket algorithm. If the values
in these two fields differ, an out-of-bounds access can occur. This is
the case because the first algorithm field (alg) is used to allocate
the correct amount of memory for a bucket of this type, while the second
algorithm field inside the bucket (b->alg) is used in the subsequent
processing.

This patch fixes the issue by adding a check that compares alg and
b->alg and aborts the processing in case they differ. Furthermore,
b->alg is set to 0 in this case, because the destruction of the crush
map also uses this field to determine the bucket type, which can again
result in an out-of-bounds access when trying to free the memory pointed
to by the fields of the bucket. To correctly free the memory allocated
for the bucket in such a case, the corresponding call to kfree is moved
from the algorithm-specific crush_destroy_bucket functions to the
generic crush_destroy_bucket().

## Remediation

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