---
id: CVE-2026-89655
title: >-
  kernel: ceph: fix UAF in __kick_flushing_caps() on cf entry freed during
  unlock (CVE-2026-89655)
summary: >-
  A flaw was found in the Linux kernel's Ceph file system component. A race
  condition exists in the `__kick_flushing_caps()` function during the handling
  of capability messages. This allows a separate process to free a data
  structure (`cf en…
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-366
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: '2026-09-15'
sourceUpdated: '2026-09-15T17:58:57+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89655.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89655.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89655'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532127'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89655'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89655'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89655.mbox
  - url: 'https://git.kernel.org/stable/c/091137821e1fc88f37e15201abf055c9494ddc61'
  - url: 'https://git.kernel.org/stable/c/01542430081014d80fc9e70e92d6647432ddb7fc'
  - url: 'https://git.kernel.org/stable/c/23eb34a53a53cb1a6dab1eeee830633207ac158d'
  - url: 'https://git.kernel.org/stable/c/19f16f04c2b014a7dd214dc1e42557d8530b16f3'
  - url: 'https://git.kernel.org/stable/c/2701431aa3cc8b23efe6890182e7b04f5e76fab5'
  - url: 'https://git.kernel.org/stable/c/fe46746087b5b9c5bb2d022df6c7819218494ced'
  - url: 'https://git.kernel.org/stable/c/2dba24dcd5050be4b7b119e6f0b01f62203b5d26'
  - url: 'https://git.kernel.org/stable/c/7af4c4f01305b0935adf6d4301b1ec407025485d'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00704
epssPercentile: 0.51905
scores:
  vendor: 7
  cna: 9.8
ingestedAt: '2026-09-14T15:23:07.450Z'
---

## Overview

A flaw was found in the Linux kernel's Ceph file system component. A race condition exists in the `__kick_flushing_caps()` function during the handling of capability messages. This allows a separate process to free a data structure (`cf entry`) while `__kick_flushing_caps()` is still iterating over it. This use-after-free (UAF) vulnerability can lead to system instability, a denial of service (DoS), or potentially privilege escalation for a local attacker.

## Vendor advisories

- **Red Hat VEX** · Moderate · 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 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89655.json)

**kernel: ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.

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