Medium [CVE-2026-64180] fix memory block reference leak on remove
This medium-severity Red Hat Linux advisory covers CVE-2026-64180 affecting Red Hat Enterprise Linux 6, Red Hat package: kernel.
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Summary
In the Linux kernel, the following vulnerability has been resolved: mm/memory_hotplug: fix memory block reference leak on remove Patch series "mm: Fix memory block leaks and locking", v2. This series fixes two memory block device reference leaks and one locking issue around the per-memory_block hwpoison counter.
This patch (of 2): remove_memory_blocks_and_altmaps() looks up each memory block with find_memory_block(), which acquires a reference to the memory block device. That reference is never dropped on this path, resulting in a leaked device reference when removing memory blocks and their altmaps.
Drop the reference after retrieving mem->altmap and clearing mem->altmap, before removing the memory block device. A flaw was found in the Linux kernel's memory hotplug component.
When memory blocks are removed, the `remove_memory_blocks_and_altmaps()` function fails to release a previously acquired reference to the memory block device. This oversight results in a memory leak, which could lead to system instability or denial of service over time due to resource exhaustion.
Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-911.
Affected Red Hat products: Red Hat Enterprise Linux 6. 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 6 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 6 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 6 days ago·verify at source
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