---
id: CVE-2026-89641
title: >-
  kernel: cifs: clear tcon after cifsFileInfo_put() in cifs_file_set_size()
  (CVE-2026-89641)
summary: >-
  A flaw was found in the Linux kernel's Common Internet File System (CIFS)
  module. This vulnerability, a use-after-free, occurs in the
  `cifs_file_set_size()` function. When a file's size is being modified, a
  critical system resource (tcon o…
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-825
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: '2026-09-15'
sourceUpdated: '2026-09-15T06:19:15+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89641.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89641.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89641'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532505'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89641'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89641'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89641.mbox
  - url: 'https://git.kernel.org/stable/c/4bea15d9c7683218f57b8c1f5f0aa75cab76af8d'
  - url: 'https://git.kernel.org/stable/c/4f18c9e7ee464aaae5cd9fccdb943b3fcb4655d4'
  - url: 'https://git.kernel.org/stable/c/b96db32fed8dfb2478d7c208f89bf383beed1535'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.0014
epssPercentile: 0.03696
scores:
  vendor: 4.7
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.473Z'
---

## Overview

A flaw was found in the Linux kernel's Common Internet File System (CIFS) module. This vulnerability, a use-after-free, occurs in the `cifs_file_set_size()` function. When a file's size is being modified, a critical system resource (tcon object) can be released too early but then accessed again. A local attacker could exploit this to cause a system crash, leading to a Denial of Service (DoS), or potentially execute unauthorized code.

## 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 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89641.json)

**kernel: cifs: clear tcon after cifsFileInfo_put() in cifs_file_set_size()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-15.

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