mm/migrate_device: clear stale mapping after freeing swapcache
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/migrate_device: clear stale mapping after freeing swapcache __migrate_device_pages() reads the folio mapping before calling folio_free_swap(). When folio_free_swap() succeeds, the folio is removed from the swap cache, but the saved mapping still points to swap_space. Passing the stale mapping to folio_migrate_mapping() makes it use the mapped-folio path for a folio that is no longer in swapcache. It can then operate on swap_space.i_pages with invalid reference accounting, eventually triggering a folio reference count BUG. After a successful split, nr still contains the number of pages in the original large folio, although each resulting page is now a separate order-0 folio. Reset nr to 1 so each split folio is processed separately, including its own swapcache removal and mapping lookup. Refresh the saved mapping after folio_free_swap() so the current folio state is used during migration.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.111, 6.18.61, 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 5 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89755
- 2026-10-03 Alias added: GHSA-f448-r8g9-p8j7
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score changed · Red Hat
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@92db780dd644590c751246187e1229d5ac2e5544 · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-29 Affected versions changed · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 Fix available: Linux/[email protected], Linux/Linux@c9c29481d5d4a985a57ece2090a324ba48e362a7 · CNA
- 2026-11-06 1 new reference · CNA
References
Other 5
- https://git.kernel.org/stable/c/92db780dd644590c751246187e1229d5ac2e5544
- https://git.kernel.org/stable/c/4fa91f7bbc4135240b67daac03fc17d9e180a331
- https://git.kernel.org/stable/c/c9c29481d5d4a985a57ece2090a324ba48e362a7
- https://git.kernel.org/stable/c/8ffedc6573a665cdc31ebe47eae7b32b78d0df83
- https://git.kernel.org/stable/c/34a00895d032a414830d41106a09329ae6c251b6
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Sources
- CVE-2026-89755 · CVE Program
- CVE-2026-89755 · NVD
- FIRST EPSS
- GHSA-f448-r8g9-p8j7 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89755 · Red Hat security data · CC BY 4.0
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