CVE-2026-89752

/// Technical description

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

mm: memcg: stop reclaim when a limit update is superseded

kernfs serializes file operations only per open file, so separate open

files can update the same memory.high or memory.max file concurrently.

Both handlers store the new limit before synchronous reclaim, but continue

to use the writer's local target in the reclaim loop. If another writer

raises or removes the limit, the first writer can continue reclaiming

toward a stale target.

For memory.max, this can leave the writer looping indefinitely once

reclaim retries are exhausted. The OOM path sees sufficient margin under

the current limit and returns true without killing, while the writer still

compares usage against its stale target and records another OOM event.

Check the current limit at the start of each reclaim iteration and stop if

it no longer matches the writer's target.

Reproducer:

Populate a cgroup with anonymous memory and disable swapping. Lowe

/// 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