# CVE-2026-89760: linux: In the Linux kernel, the following vulnerability has been resolved:  mm, swap: don't free a hibernation slot that is...

CVE-2026-89760 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89760 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-89760
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026

## 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 can trigger silent memory corruption, process crashes, or data instability across completely unrelated userspace applications - typically occurring when uswsusp is preparing the hibernation image.  I found this while working on giving hibernation slots their own marker in the swap table, which I had discussed with Kairui.  (https://lore.kernel.org/linux-mm/abp7aDgYLrxF3Me8@KASONG-MC4/) As far as I know there are no reports, so there is no Reported-by/Closes to add.  Check for a cached folio before freeing.  The slot is then left in the ordinary state where only the swap cache holds it, and it is freed when the folio leaves the cache, either through the reclaim below or through normal reclaim later.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89760](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89760.md) | Sep 23, 2026 |

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