{"id":"CVE-2026-89755","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89755","summary":"mm/migrate_device: clear stale mapping after freeing swapcache","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/migrate_device: clear stale mapping after freeing swapcache\n\n__migrate_device_pages() reads the folio mapping before calling\nfolio_free_swap().  When folio_free_swap() succeeds, the folio is removed\nfrom the swap cache, but the saved mapping still points to swap_space.\n\nPassing the stale mapping to folio_migrate_mapping() makes it use the\nmapped-folio path for a folio that is no longer in swapcache.  It can then\noperate on swap_space.i_pages with invalid reference accounting,\neventually triggering a folio reference count BUG.\n\nAfter a successful split, nr still contains the number of pages in the\noriginal large folio, although each resulting page is now a separate\norder-0 folio.  Reset nr to 1 so each split folio is processed separately,\nincluding its own swapcache removal and mapping lookup.\n\nRefresh the saved mapping after folio_free_swap() so the current folio\nstate is used during migration.","published":"2026-09-11T19:46:58.295Z","modified":"2026-09-14T03:46:30.299377947Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"7.2.4"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/34a00895d032a414830d41106a09329ae6c251b6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8ffedc6573a665cdc31ebe47eae7b32b78d0df83"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89755.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89755"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:46:30.299377947Z"}}