Use After Free in Linux

CVE-2026-31589

In the Linux kernel, the following vulnerability has been resolved: mm: call ->free_folio() directly in folio_unmap_invalidate() We can only call filemap_free_folio() if we have a reference to (or hold a lock on) the mapping. Otherwise, we've already removed the folio from the mapping so it no longer pins the mapping and the mapping can be removed, causing a use-after-free when accessing mapping->a_ops. Follow the same pattern as __remove_mapping() and load the free_folio function pointer before dropping the lock on the mapping. That lets us make filemap_free_folio() static as this was the only caller outside filemap.c.

Vulnerability class: Use-After-Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (49.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-31589: held from 0.004 to 0.007.

EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.002

Affected products

  • Linux — versions fb7d3bc4149395c1ae99029c852eab6c28fc3c88, 6.18.27, 7.1-rc1
  • Linux Kernel

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-31589?
CVE-2026-31589 is a critical-severity vulnerability in Linux, classified under Use After Free. CVSS score: 9.8/10. Published 2026-04-24.
How severe is CVE-2026-31589?
Critical severity. CVSS v3 base score is 9.8 out of 10.