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PatchSiren cyber security CVE debrief

CVE-2026-53180 Linux CVE debrief

A HIGH severity vulnerability, CVE-2026-53180, was resolved in the Linux kernel. The vulnerability was caused by a livelock in tmigr_handle_remote_up(), which could lead to a denial-of-service attack. The issue arose from the incorrect assumption that the local softirq path had already handled the CPU's timers. This assumption was wrong because jiffies could advance after handling the CPU's global timers and before evaluating the expiry times. As a result, a timer that expired after the CPU local timer wheel advanced was ignored, and its callback was never invoked or removed from the timer wheel. The vulnerability had a CVSS score of 7.5 and was patched by calling timer_expire_remote() unconditionally.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-25
Original CVE updated
2026-06-28
Advisory published
2026-06-25
Advisory updated
2026-06-28

Who should care

System administrators and security teams responsible for Linux kernel-based systems should be aware of this vulnerability. They should check their systems for exposure and apply the patch to prevent potential denial-of-service attacks. Linux kernel developers and maintainers should also review the patch and ensure it is integrated into their systems.

Technical summary

The vulnerability was caused by a livelock in tmigr_handle_remote_up() due to an incorrect assumption about the handling of CPU timers. The issue led to a timer being ignored and its callback never invoked or removed from the timer wheel. The vulnerability was resolved by calling timer_expire_remote() unconditionally, which has minimal overhead for the common case. The patch ensures that timers are properly handled and callbacks are invoked.

Defensive priority

Apply the patch to prevent potential denial-of-service attacks. Review system logs for signs of exploitation.

Recommended defensive actions

  • Apply the patch by updating the Linux kernel to the latest version.
  • Review system logs for signs of exploitation.
  • Check system configurations for exposure.
  • Monitor system performance for potential denial-of-service attacks.
  • Ensure Linux kernel developers and maintainers review and integrate the patch.

Evidence notes

The vulnerability was resolved by calling timer_expire_remote() unconditionally. The patch has minimal overhead for the common case. The issue arose from an incorrect assumption about the handling of CPU timers. The vulnerability had a CVSS score of 7.5 and was classified as HIGH severity.

Official resources

This article is AI-assisted and based on the supplied source corpus.