---
id: CVE-2026-64559
title: 's390/pkey: Check length in PKEY_VERIFYPROTK ioctl'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/pkey: Check length in PKEY_VERIFYPROTK ioctl

  Explicitly check the buffer length request structure provided by
  user-space and fail, if it exceeds the buffer size.
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
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 <
    0a9e34ccbe772b8f321388cdbdf4f22b94e513e7
  - >-
    Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 <
    693bf91d4db134f9b1c2840c8e287eee3d993bac
  - >-
    Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 <
    7e7e03848c918aa0acad5ffd75d929e3afec1554
  - >-
    Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 <
    b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970
  - Linux 6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:42:43.749651Z'
published: '2026-07-29'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:52:52.832Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64559'
references:
  - url: 'https://git.kernel.org/stable/c/0a9e34ccbe772b8f321388cdbdf4f22b94e513e7'
  - url: 'https://git.kernel.org/stable/c/693bf91d4db134f9b1c2840c8e287eee3d993bac'
  - url: 'https://git.kernel.org/stable/c/7e7e03848c918aa0acad5ffd75d929e3afec1554'
  - url: 'https://git.kernel.org/stable/c/b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970'
tags:
  - cve.org
epss: 0.0012
epssPercentile: 0.01677
ingestedAt: '2026-10-16T17:24:46.835Z'
---

## Overview

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

s390/pkey: Check length in PKEY_VERIFYPROTK ioctl

Explicitly check the buffer length request structure provided by
user-space and fail, if it exceeds the buffer size.

## Affected

- `Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 < 0a9e34ccbe772b8f321388cdbdf4f22b94e513e7`
- `Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 < 693bf91d4db134f9b1c2840c8e287eee3d993bac`
- `Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 < 7e7e03848c918aa0acad5ffd75d929e3afec1554`
- `Linux >= 8fcc231ce3bea12b78bb94b280cdc03cff342435 < b3d4ab2d7df9426f7f1d3671d7e2108f2ca6e970`
- `Linux 6.12`

## Remediation

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