EUVD-2026-55458 · Published Aug 10, 2026
In the Linux kernel, the following vulnerability has been resolved: watchdog: pretimeout: Fix UAF in watchdog_unregister_governor() When a watchdog governor is unregistered, it updates existing watchdog devices that were using this governor by falling back to `default_gov`. If the governor being unregistered is currently set as `default_gov`, the `default_gov` is never cleared. This leads to 2 use-after-free issues: 1. New watchdog devices registered after this point will inherit the dangling `default_gov`. 2. Existing watchdog devices using the unregistered governor will have their `wdd->gov` reassigned to the dangling `default_gov`. Fix the UAF by clearing `default_gov` if it matches the governor being unregistered.
References
- https://git.kernel.org/stable/c/0ca252720f0e38411cfec3431db9bb1aed0a412c
- https://git.kernel.org/stable/c/2e47b91b9b4020fcc01def14d6b6556d66074cf4
- https://git.kernel.org/stable/c/7362ba0f9c96ac3ad6a2ca3995bd9fc9a28a8661
- https://git.kernel.org/stable/c/7993d626983cc58fbde9607333cfd2d57725c197
- https://git.kernel.org/stable/c/7d1658b066de30f4b23afc14814d22416a971e6e
- https://git.kernel.org/stable/c/472ec1e34ff0bb26379805cae808f658cce58c35
Potentially impacted assets
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