---
id: CVE-2026-89656
title: 'kernel: libceph: reject buckets with mismatched CRUSH ids (CVE-2026-89656)'
summary: >-
  A flaw was found in libceph within the Linux kernel. This vulnerability allows
  a local attacker to craft a malformed CRUSH map, which is used for data
  placement. By doing so, one data bucket can be made to reuse another bucket's
  memory wor…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
cwe: CWE-787
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T07:46:40+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89656.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89656.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89656'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532365'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89656'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89656'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89656.mbox
  - url: 'https://git.kernel.org/stable/c/ee59040d6ed1a5f8d10d27174b8f32c90ca8e89a'
  - url: 'https://git.kernel.org/stable/c/baad5875fdd2f5e248250fc3519bb045d64f1716'
  - url: 'https://git.kernel.org/stable/c/4aeb93daadf388e72073abc204312dd364eeb30a'
  - url: 'https://git.kernel.org/stable/c/6e5c6ce252b1eccfd41670a5cf95ab44f7ba7022'
  - url: 'https://git.kernel.org/stable/c/3516a4131c4e45d62ee4e42e82c36930e8c1fbbd'
  - url: 'https://git.kernel.org/stable/c/00562ccd4e88d092b9b851df50fad20442bfeb24'
  - url: 'https://git.kernel.org/stable/c/79900d978158b2d80eef952fc41b9e4dc58d7b83'
  - url: 'https://git.kernel.org/stable/c/3cde4a8302301679937474a5f7a851394cc1bd11'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00521
epssPercentile: 0.4321
scores:
  vendor: 7
  cna: 9.8
ingestedAt: '2026-09-14T15:23:07.450Z'
---

## Overview

A flaw was found in libceph within the Linux kernel. This vulnerability allows a local attacker to craft a malformed CRUSH map, which is used for data placement. By doing so, one data bucket can be made to reuse another bucket's memory workspace, leading to an out-of-bounds write. This memory corruption could result in a denial of service or potentially lead to privilege escalation.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89656.json)

**kernel: libceph: reject buckets with mismatched CRUSH ids** — rated Important by Red Hat. Released 2026-09-11, updated 2026-09-16.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

Not affected:

- Red Hat Enterprise Linux 6

## Remediation

Affected