SB20260727143 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel io_uring

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Main Vulnerability Database SB20260727143

SB20260727143 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel io_uring

Published: July 27, 2026

Security Bulletin ID SB20260727143
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-64425)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper state management in io_worker_handle_work() in io_uring/io-wq.c when processing linked work items during io_uring worker exit handling. A local user can submit linked work and trigger ring closure to cause a denial of service.

Exploitation requires a race condition where worker exit begins after the first linked item has started but before the remaining linked items are processed.


Remediation

Install update from vendor's website.

References