SB20261103136 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel keys

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Main Vulnerability Database SB20261103136

SB20261103136 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel keys

Published: November 3, 2026

Security Bulletin ID SB20261103136
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Data manipulation

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-2026-99245)

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

CVSSv4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to bypass a keyring restriction and link a rejected key into the keyring.

The vulnerability exists due to a time-of-check time-of-use race condition in key_reject_and_link() when checking keyring restrictions before acquiring the keyring semaphore. A local user can race a key rejection and linking operation against a concurrent keyring_restrict() operation to link a rejected key despite a newly installed restriction.


Remediation

Install update from vendor's website.

References