CVE-2026-52980

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

sched/fair: Clear rel_deadline when initializing forked entities

A yield-triggered crash can happen when a newly forked sched_entity

enters the fair class with se->rel_deadline unexpectedly set.

The failing sequence is:

1. A task is forked while se->rel_deadline is still set.

2. __sched_fork() initializes vruntime, vlag and other sched_entity

state, but does not clear rel_deadline.

3. On the first enqueue, enqueue_entity() calls place_entity().

4. Because se->rel_deadline is set, place_entity() treats se->deadline

as a relative deadline and converts it to an absolute deadline by

adding the current vruntime.

5. However, the forked entity's deadline is not a valid inherited

relative deadline for this new scheduling instance, so the conversion

produces an abnormally large deadline.

6. If the task later calls sched_yield(), yield_task_fair() advances

se->vruntime to se->deadlin

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References