CVE-2026-89760 - mm, swap: don't free a hibernation slot that is in the swap cache
Brief
CVE ID : CVE-2026-89760
Published : Sept. 11, 2026, 8:20 p. m.
- 32 minutes ago
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.