CVE-2026-89760

/// Technical description

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

mm, swap: don't free a hibernation slot that is in the swap cache

A slot with a folio in the swap cache is freed when the folio leaves the

cache, not when its count drops. swap_put_entries_cluster() follows that

rule. swap_free_hibernation_slot() does not, it calls

__swap_cluster_free_entries() whether or not a folio sits on the slot.

Cluster readahead can put one there. It walks a raw page_cluster sized

window of offsets around the faulting entry, and a hibernation slot passes

__swap_cache_add_check() because it is not a folio and its count is not

zero. Freeing the slot then clears the entry under that folio.

The folio is now unreachable from the swap table, and the offset goes back

to the allocator. The folio is still on the LRU though, so reclaim can

pick it up later. It then takes the old offset out of folio->swap and

overwrites the table entry there, which by then may belong to someone

else.

This bug ca

/// 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