Medium [CVE-2026-52930] serialize orphan cleanup with shm_nattch updates
This medium-severity Red Hat Linux advisory covers CVE-2026-52930 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
In the Linux kernel, the following vulnerability has been resolved: ipc/shm: serialize orphan cleanup with shm_nattch updates shm_destroy_orphaned() walks the shm idr under shm_ids(ns).rwsem, but that does not serialize all fields tested by shm_may_destroy().
In particular, shm_nattch is updated while holding shm_perm.lock, and attach paths can do that without holding the rwsem. Do not decide that an orphaned segment is unused before taking the object lock.
Move the shm_may_destroy() check under shm_perm.lock, matching the other destroy paths, and unlock the segment when it no longer qualifies for removal. A flaw was found in the Linux kernel's inter-process communication (IPC) shared memory (shm) component.
A synchronization issue exists where orphaned shared memory segments might be incorrectly destroyed while still in use due to a lack of serialization between cleanup and attachment updates. This could lead to system instability or a denial of service.
Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-367.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 9 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 9 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 9 days ago·verify at source
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