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CVE-2026-72389 Linux CVE debrief

A use-after-free vulnerability was found in the Linux kernel's bridge module. The STP topology change timer was not properly shut down when the bridge was administratively down, leading to a potential use-after-free when the bridge was deleted. This vulnerability has been resolved in the Linux kernel. Affected systems may be vulnerable to potential use-after-free errors if the bridge module is not properly shut down. The vulnerability was caused by missing checks for 'IFF_UP' before arming the STP timers, which could lead to a use-after-free when the bridge was deleted. Further review is needed to determine the full scope of affected systems and potential impact. Defenders should verify system configurations, review logs for suspicious activity, and ensure the bridge module is properly shut down when not in use.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-15
Original CVE updated
2026-08-15
Advisory published
2026-08-15
Advisory updated
2026-08-15

Who should care

Linux kernel developers and users who rely on the bridge module, as well as security teams and vulnerability management teams responsible for ensuring the security of Linux-based systems. System administrators and operators who manage Linux systems with the bridge module enabled should also be aware of this vulnerability and take steps to mitigate it.

Technical summary

The Linux kernel's bridge module has a use-after-free vulnerability. The STP topology change timer is not properly shut down when the bridge is administratively down, leading to a potential use-after-free when the bridge is deleted. This vulnerability has been resolved in the Linux kernel. Affected systems may be vulnerable to potential use-after-free errors if the bridge module is not properly shut down.

Defensive priority

Medium

Recommended defensive actions

  • Review and apply the Linux kernel patch to fix the use-after-free vulnerability
  • Ensure the bridge module is properly shut down when not in use
  • Monitor the system for potential use-after-free errors
  • Perform a thorough review of system configurations to identify potential exposure
  • Implement compensating controls for exposed systems while remediation is scheduled and verified
  • Track exceptions and retest remediated assets to ensure the vulnerability is fully resolved
  • Review relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record was published on 2026-08-15T06:22:12.397Z. The NVD entry is currently Received. The vulnerability was resolved in the Linux kernel. Further review is needed to determine the full scope of affected systems and potential impact. Defenders should verify system configurations, review logs for suspicious activity, and ensure the bridge module is properly shut down when not in use.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-15T06:22:12.397Z and has not been modified since then.