Shinichiro

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** The Linux kernel contains a flaw in the MMCID management code related to handling CPU ID (CID) transitions. Specifically, the issue arises when a task exits while in a transitional state, leading to an out-of-bounds access during CID removal. The `sched mm cid exit()` function incorrectly assumes the CID is CPU-owned, potentially causing issues when the `TRANSIT` flag is set. This can occur when a task switches between per-CPU and per-task CID modes without proper synchronization, resulting in a use-after-free condition. The vulnerability was identified through KASAN (Kernel Address Sanitizer) and reported by Shinichiro. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.