CVE Catalog

CVE-2026-89755

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.14%

4th percentile - higher than 4% of all known CVEs

Summary

In the Linux kernel, __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, leading to use of a stale mapping and invalid reference accounting, eventually triggering a folio reference count BUG.

Risk Assessment

The flaw can trigger a critical kernel BUG and system crash (panic) during device memory migration. In environments using page migration from swap memory this may lead to service unavailability.

Recommendation

Update the Linux kernel to a version with the fix that refreshes the saved mapping after folio_free_swap() and resets nr to 1 after folio split. Testing memory migration in a staging environment is also recommended.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS