CVE-2025-38686
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-04

Last updated on: 2025-11-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: userfaultfd: fix a crash in UFFDIO_MOVE when PMD is a migration entry When UFFDIO_MOVE encounters a migration PMD entry, it proceeds with obtaining a folio and accessing it even though the entry is swp_entry_t. Add the missing check and let split_huge_pmd() handle migration entries. While at it also remove unnecessary folio check. [[email protected]: remove extra folio check, per David]
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Meta Information
Published
2025-09-04
Last Modified
2025-11-24
Generated
2026-06-16
AI Q&A
2025-09-04
EPSS Evaluated
2026-06-15
NVD
CVE-2025-38686
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.17
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
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CWE ID Description
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Executive Summary

This vulnerability occurs in the Linux kernel's userfaultfd feature, specifically in the UFFDIO_MOVE operation. When UFFDIO_MOVE encounters a migration Page Middle Directory (PMD) entry, it incorrectly tries to obtain and access a folio even though the entry is of type swp_entry_t (a swap entry). The fix involves adding a missing check to properly handle migration entries by letting the split_huge_pmd() function manage them, and removing an unnecessary folio check to prevent a crash.

Impact Analysis

This vulnerability can cause the Linux kernel to crash when the UFFDIO_MOVE operation encounters a migration PMD entry without the proper checks. Such a crash can lead to system instability or denial of service, potentially disrupting normal operations on affected systems.

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