mm/migrate_device: clear stale mapping after freeing swapcache
CVE-2026-89755 · published 11 Sept 2026
How serious is it
- Severity: high, CVSS score 7.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-89755?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: df263d9a7dffee94ca5391120ee3b0587efa07f1 to < 92db780dd644590c751246187e1229d5ac2e5544, df263d9a7dffee94ca5391120ee3b0587efa07f1 to < 4fa91f7bbc4135240b67daac03fc17d9e180a331, df263d9a7dffee94ca5391120ee3b0587efa07f1 to < 8ffedc6573a665cdc31ebe47eae7b32b78d0df83, df263d9a7dffee94ca5391120ee3b0587efa07f1 to < 34a00895d032a414830d41106a09329ae6c251b6
- Linux Linux: 6.6
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/92db780dd644590c751246187e1229d5ac2e5544
- git.kernel.org/stable/c/4fa91f7bbc4135240b67daac03fc17d9e180a331
- git.kernel.org/stable/c/8ffedc6573a665cdc31ebe47eae7b32b78d0df83
- git.kernel.org/stable/c/34a00895d032a414830d41106a09329ae6c251b6
Merged from CVE List. Last updated 26 Oct 2026. All vulnerabilities · RSS · JSON