{"id":"CVE-2026-89755","title":"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()","summary":"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…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= df263d9a7dffee94ca5391120ee3b0587efa07f1 < 4fa91f7bbc4135240b67daac03fc17d9e180a331","Linux >= df263d9a7dffee94ca5391120ee3b0587efa07f1 < 8ffedc6573a665cdc31ebe47eae7b32b78d0df83","Linux >= df263d9a7dffee94ca5391120ee3b0587efa07f1 < 34a00895d032a414830d41106a09329ae6c251b6","Linux 6.6"],"published":"2026-09-11","updated":"2026-09-21","sourceUpdated":"2026-09-21T14:17:26.320","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89755","references":[{"url":"https://git.kernel.org/stable/c/34a00895d032a414830d41106a09329ae6c251b6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4fa91f7bbc4135240b67daac03fc17d9e180a331","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8ffedc6573a665cdc31ebe47eae7b32b78d0df83","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89755.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89755"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532241"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89755"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89755"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89755.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00143,"epssPercentile":0.03991,"scores":{"nvd":7.8,"cna":7.8,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.472Z","slug":"CVE-2026-89755","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89755.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208367,"id":"CVE-2026-89755","ts":1789997912114,"field":"cvss","old":"4.1","new":"7.8"},{"seq":208366,"id":"CVE-2026-89755","ts":1789997912114,"field":"severity","old":"medium","new":"high"},{"seq":202962,"id":"CVE-2026-89755","ts":1789403733130,"field":"cvss","old":"7.8","new":"4.1"},{"seq":202961,"id":"CVE-2026-89755","ts":1789403733130,"field":"severity","old":"high","new":"medium"},{"seq":197674,"id":"CVE-2026-89755","ts":1789384318342,"field":"cvss","old":"4.1","new":"7.8"},{"seq":197673,"id":"CVE-2026-89755","ts":1789384318342,"field":"severity","old":"medium","new":"high"},{"seq":183647,"id":"CVE-2026-89755","ts":1789356676247,"field":"cvss","old":"7.8","new":"4.1"},{"seq":183646,"id":"CVE-2026-89755","ts":1789356676247,"field":"severity","old":"high","new":"medium"},{"seq":153642,"id":"CVE-2026-89755","ts":1789285351683,"field":"cvss","old":null,"new":"7.8"},{"seq":153641,"id":"CVE-2026-89755","ts":1789285351683,"field":"severity","old":"none","new":"high"},{"seq":147502,"id":"CVE-2026-89755","ts":1789270211160,"field":"cvss","old":null,"new":"4.1"},{"seq":147501,"id":"CVE-2026-89755","ts":1789270211160,"field":"severity","old":"none","new":"medium"},{"seq":109260,"id":"CVE-2026-89755","ts":1789183731182,"field":"cvss","old":null,"new":"4.1"},{"seq":109259,"id":"CVE-2026-89755","ts":1789183731182,"field":"severity","old":"none","new":"medium"}]}