CVE-2026-43418

A flaw was found in the Linux kernel's sched/mmcid component. When new tasks are created concurrently, a race condition can occur where a task is accounted as a Memory Management Context ID (MMCID) user before it is fully registered in the system's task lists. This can lead to an incorrect allocation of Context IDentifiers (CIDs). As a result, the system may fail to acquire a necessary CID, causing the machine to stall and resulting in a Denial of Service (DoS).

Red Hat acknowledges the upstream Linux kernel correction for «sched/mmcid» as described in COMMENT_ZERO. Fixes are delivered through standard kernel errata for supported products. Operational exposure depends on whether this subsystem or driver is active in your configuration.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.