SB2026091219 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel fs
Published: September 12, 2026
Security Bulletin ID
SB2026091219
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Information disclosure
Breakdown by Severity
- 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-2026-89766)
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:L/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to disclose namespace information.
The vulnerability exists due to a time-of-check time-of-use race condition in pidfd_ioctl() when performing PIDFD_GET_*_NAMESPACE ioctls while a target task executes a setuid binary. A local user can race a namespace ioctl with the target task's execve operation to disclose namespace information.
Remediation
Install update from vendor's website.