---
id: CVE-2026-89657
title: >-
  kernel: libceph: validate OSD extent maps before cursor advance
  (CVE-2026-89657)
summary: >-
  A flaw was found in libceph in the Linux kernel. A malicious or compromised
  authenticated Ceph Object Storage Device (OSD) peer could send a specially
  crafted sparse-read reply that lacks proper validation of extent maps. This
  could cause …
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-125
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T22:12:40+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89657.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89657.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89657'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532301'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89657'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89657'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89657.mbox
  - url: 'https://git.kernel.org/stable/c/94ae5145c520618802b0a24c047dcd5f05835db8'
  - url: 'https://git.kernel.org/stable/c/058ffa81f9440c5b4714685611cf697fd3739ec9'
  - url: 'https://git.kernel.org/stable/c/2571b35883268a266554e80d368e67fdfea7fb9d'
  - url: 'https://git.kernel.org/stable/c/201db408872ca12cf09e36bf0f560138c3dcfa1c'
  - url: 'https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00603
epssPercentile: 0.47572
scores:
  vendor: 7
  cna: 7.5
ingestedAt: '2026-09-14T15:23:07.450Z'
---

## Overview

A flaw was found in libceph in the Linux kernel. A malicious or compromised authenticated Ceph Object Storage Device (OSD) peer could send a specially crafted sparse-read reply that lacks proper validation of extent maps. This could cause the client to advance its message-data cursor beyond the request buffer, leading to a kernel crash and a Denial of Service (DoS).

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89657.json)

**kernel: libceph: validate OSD extent maps before cursor advance** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-18.

Affected:

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

No fix planned:

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

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4

## Remediation

Affected