CVE-2025-40272: In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix use-after-free race in fault handler When a page fault occurs ...

Description

In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix use-after-free race in fault handler When a page fault occurs in a secret memory file created with `memfd_secret(2)`, the kernel will allocate a new folio for it, mark the underlying page as not-present in the direct map, and add it to the file mapping. If two tasks cause a fault in the same page concurrently, both could end up allocating a folio and removing the page from the direct map, but only one would succeed in adding the folio to the file mapping. The task that failed undoes the effects of its attempt by (a) freeing the folio again and (b) putting the page back into the direct map. However, by doing these two operations in this order, the page becomes available to the allocator again before it is placed back in the direct mapping. If another task attempts to allocate the page between (a) and (b), and the kernel tries to access it via the direct map, it would result in a supervisor not-present page fault. Fix the ordering to restore the direct map before the folio is freed.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.17%

7.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49, < bb1c19636aedae39360e6fdbcaef4f2bcff25785; >= 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49, < 1e4643d6628edf9c0047b1f8f5bc574665025acb; >= 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49, < 42d486d35a4143cc37fc72ee66edc99d942dd367; >= 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49, < 52f2d5cf33de9a8f5e72bbb0ed38282ae0bc4649; >= 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49, < 4444767e625da46009fc94a453fd1967b80ba047; >= 1507f51255c9ff07d75909a84e7c0d7f3c4b2f49, < 6f86d0534fddfbd08687fa0f01479d4226bc3c3d
Linux	Linux	5.14

References

Timeline

Published: Dec 6, 2025
Last Modified: Jul 30, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40272?

In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: fix use-after-free race in fault handler When a page fault occurs in a secret memory file created with `memfd_secret(2)`, the kernel will allocate a new folio for it, mark the underlying page as not-present in the direct map, and add it to the file mapping. If two tasks cause a fault in the same page concurrently, both could end up allocating a folio and removing the page from the direct map, but only one would succeed in adding the folio to the file mapping. The task that failed undoes the effects of its attempt by (a) freeing the folio again and (b) putting the page back into the direct map. However, by doing these two operations in this order, the page becomes available to the allocator again before it is placed back in the direct mapping. If another task attempts to allocate the page between (a) and (b), and the kernel tries to access it via the direct map, it would result in a supervisor not-present page fault. Fix the ordering to restore the direct map before the folio is freed.

How severe is CVE-2025-40272?

CVE-2025-40272 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40272?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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