---
id: CVE-2026-80959
title: 'dm-pcache: bound the persisted tail-position offset'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dm-pcache: bound the persisted tail-position offset

  cache_pos_decode() takes the persisted key_tail and dirty_tail seg_off from
  the cache device and addresses within t…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-125
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 <
    ffd9a214a94f9928e54856f42b1cc3e33fb10e36
  - >-
    Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 <
    8bf7a06ca3c1611809725f58cfd573f2ffbda75f
  - >-
    Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 <
    d1898576090a10d2ac2715218a652e78fb65a6b0
  - Linux 6.18
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:45:43.213Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80959'
references:
  - url: 'https://git.kernel.org/stable/c/ffd9a214a94f9928e54856f42b1cc3e33fb10e36'
  - url: 'https://git.kernel.org/stable/c/8bf7a06ca3c1611809725f58cfd573f2ffbda75f'
  - url: 'https://git.kernel.org/stable/c/d1898576090a10d2ac2715218a652e78fb65a6b0'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80959.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-80959'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532361'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-80959'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80959'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80959.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00173
epssPercentile: 0.06727
scores:
  cna: 7.8
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.476Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

dm-pcache: bound the persisted tail-position offset

cache_pos_decode() takes the persisted key_tail and dirty_tail seg_off from
the cache device and addresses within the segment with it. A seg_off at or
past the segment data_size, controllable by whoever supplies the device
(CAP_SYS_ADMIN), reads past the segment data.

Reject a decoded seg_off that is not below the segment data_size.

## Affected

- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < ffd9a214a94f9928e54856f42b1cc3e33fb10e36`
- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < 8bf7a06ca3c1611809725f58cfd573f2ffbda75f`
- `Linux >= 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 < d1898576090a10d2ac2715218a652e78fb65a6b0`
- `Linux 6.18`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80959.json)