Executive brief
A vulnerability in the Linux kernel's timer management system can cause system stalls or unresponsiveness. The issue occurs when the kernel fails to properly reset internal flags used to prevent timer starvation, leading to missed timer interrupts. This can result in a denial-of-service condition where the operating system stops responding to scheduled tasks or user input.
Technical details
The Linux kernel's clockevents subsystem contains a logic error where the 'next_event_forced' flag, part of a mechanism to prevent timer interrupt starvation, is not reset in several critical code paths. Specifically, the flag remains stale during clock event state transitions, when arming non-forced events, and within the suspend wakeup handler. If a non-forced event is scheduled far in the future while this flag is incorrectly set, the kernel may fail to rearm the timer, leading to missed interrupts and CPU stalls. This is a local denial-of-service vulnerability reachable by an attacker with local access. Patches have been released for various stable kernel branches, including the 7.0.y series.
Affected products
- Linux Linux Kernel versions up to (excluding) 7.0.1
Timeline
- 2026-04-14: other: Initial patch authored by Thomas Gleixner
- 2026-04-24: disclosed
- 2026-04-24: advisory