---
id: CVE-2026-80927
title: 'timekeeping: Check the return value of tk_get_aux_ts64 in __do_adjtimex()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  timekeeping: Check the return value of tk_get_aux_ts64 in __do_adjtimex()

  If the auxiliary clock is disabled during tk_get_aux_ts64() but is enabled
  before tks->clock_…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe:
  - CWE-367
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 4eca49d0b621b314ac7c80f363932ec6f6c8abc8 <
    fecf1e37775269ad38c172b468ad4ecc3968aa63
  - >-
    Linux >= 4eca49d0b621b314ac7c80f363932ec6f6c8abc8 <
    bc59dac50cb45a725f7a50760c7cc72a0964f722
  - >-
    Linux >= 4eca49d0b621b314ac7c80f363932ec6f6c8abc8 <
    4b61084b11bcecce86d03804ff30f8d7b465593c
  - Linux 6.17
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:45:11.147Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80927'
references:
  - url: 'https://git.kernel.org/stable/c/fecf1e37775269ad38c172b468ad4ecc3968aa63'
  - url: 'https://git.kernel.org/stable/c/bc59dac50cb45a725f7a50760c7cc72a0964f722'
  - url: 'https://git.kernel.org/stable/c/4b61084b11bcecce86d03804ff30f8d7b465593c'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80927.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-80927'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532325'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-80927'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80927'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80927.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00206
epssPercentile: 0.1061
ingestedAt: '2026-09-14T00:35:28.532Z'
---

## Overview

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

timekeeping: Check the return value of tk_get_aux_ts64 in __do_adjtimex()

If the auxiliary clock is disabled during tk_get_aux_ts64() but is enabled
before tks->clock_valid is checked, then uninitialized stackdata will be
used in the calculations and indirectly leaked to userspace.

The same race window also exists after this change and also for the core
timekeeper. But in these cases the only effect would be incorrect
adjustments and this is userspace's responsibility to avoid this.

## Affected

- `Linux >= 4eca49d0b621b314ac7c80f363932ec6f6c8abc8 < fecf1e37775269ad38c172b468ad4ecc3968aa63`
- `Linux >= 4eca49d0b621b314ac7c80f363932ec6f6c8abc8 < bc59dac50cb45a725f7a50760c7cc72a0964f722`
- `Linux >= 4eca49d0b621b314ac7c80f363932ec6f6c8abc8 < 4b61084b11bcecce86d03804ff30f8d7b465593c`
- `Linux 6.17`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80927.json)