CVE-2025-38686

userfaultfd: fix a crash in UFFDIO_MOVE when PMD is a migration entry

MEDIUM
5.5
CVSS Score
Published: September 4, 2025 at 03:32 PM UTC
Updated: October 19, 2026 at 09:10 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%

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]

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.13 ≤ v < 6.15.116.16 ≤ v < 6.16.26.8 ≤ v < 6.12.436.176.17 rc16.8adef440691bab824e39c1b17382322d195e1fab0
Vendor states this is fixed in 1202abad7a7ccd28c426d2844771a387b07629a4 (fixed)
Vendor states this is fixed in 7f1101a0a181243ad587ececdffc4845f035549f (fixed)
Vendor states this is fixed in aba6faec0103ed8f169be8dce2ead41fcb689446 (fixed)
Vendor states this is fixed in bb81c18dbd42650c844e160cafa7cbb20243a96a (fixed)
Vendor states this is fixed in 6.12.43 (unaffected)
Vendor states this is fixed in 6.15.11 (unaffected)
Vendor states this is fixed in 6.16.2 (unaffected)
Vendor states this is fixed in 6.17 (unaffected)
Vendor states this is fixed in 6.8 (unaffected)

References (4)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/1202abad7a7ccd28c426d2844771a387b07629a4
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/7f1101a0a181243ad587ececdffc4845f035549f
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/aba6faec0103ed8f169be8dce2ead41fcb689446
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/bb81c18dbd42650c844e160cafa7cbb20243a96a

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
NVD-CWE-noinfo

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