---
id: CVE-2025-39689
title: >-
  kernel: ftrace: Also allocate and copy hash for reading of filter files
  (CVE-2025-39689)
summary: >-
  A flaw was found in the Linux kernel. A Use-After-Free (UAF) vulnerability
  exists in the ftrace subsystem during the reading of tracing filter files. The
  filter reader retains a direct pointer to global filter data rather than
  creating an …
severity: medium
cvss: 6.4
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
cwe: CWE-694
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 8
  - enterprise_linux 9
published: '2025-09-05'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T22:56:04+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39689.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39689.json
  - url: 'https://access.redhat.com/security/cve/CVE-2025-39689'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2393517'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2025-39689'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-39689'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2025090546-CVE-2025-39689-f538@gregkh/T
  - url: 'https://git.kernel.org/stable/c/12064e1880fc9202be75ff668205b1703d92f74f'
  - url: 'https://git.kernel.org/stable/c/c4cd93811e038d19f961985735ef7bb128078dfb'
  - url: 'https://git.kernel.org/stable/c/e0b6b223167e1edde5c82edf38e393c06eda1f13'
  - url: 'https://git.kernel.org/stable/c/a40c69f4f1ed96acbcd62e9b5ff3a596f0a91309'
  - url: 'https://git.kernel.org/stable/c/3b114a3282ab1a12cb4618a8f45db5d7185e784a'
  - url: 'https://git.kernel.org/stable/c/c591ba1acd081d4980713e47869dd1cc3d963d19'
  - url: 'https://git.kernel.org/stable/c/64db338140d2bad99a0a8c6a118dd60b3e1fb8cb'
  - url: 'https://git.kernel.org/stable/c/bfb336cf97df7b37b2b2edec0f69773e06d11955'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00184
epssPercentile: 0.07953
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:53:25.266469Z'
scores:
  vendor: 6.4
  cna: 7.8
ingestedAt: '2026-10-15T05:52:46.080Z'
---

## Overview

A flaw was found in the Linux kernel. A Use-After-Free (UAF) vulnerability exists in the ftrace subsystem during the reading of tracing filter files. The filter reader retains a direct pointer to global filter data rather than creating an independent copy, which allows concurrent updates to free the underlying memory while it is still referenced. A local attacker can exploit this flaw to cause a Denial of Service (DoS) through a system crash or potentially achieve privilege escalation.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39689.json)

**kernel: ftrace: Also allocate and copy hash for reading of filter files** — rated Moderate by Red Hat. Released 2025-09-05, updated 2026-10-16.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9

No fix planned:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9

Not affected:

- Red Hat Enterprise Linux 7

## Remediation

Out of support scope

Workarounds / mitigations:

- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.