mm/huge_memory: fix dereferencing invalid pmd migration entry

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-37958
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-05-20 16:15:34 UTC
Updated2026-11-05 21:17:59 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: fix dereferencing invalid pmd migration entry When migrating a THP, concurrent access to the PMD migration entry during a deferred split scan can lead to an invalid address access, as illustrated below. To prevent this invalid access, it is necessary to check the PMD migration entry and return early. In this context, there is no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the equality of the target folio. Since the PMD migration entry is locked, it cannot be served as the target. Mailing list discussion and explanation from Hugh Dickins: "An anon_vma lookup points to a location which may contain the folio of interest, but might instead contain another folio: and weeding out those other folios is precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of replacing the wrong folio" comment a few lines above it) is for." BUG: unable to handle page fault for address: ffffea60001db008 CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60 Call Trace: <TASK> try_to_migrate_one+0x28c/0x3730 rmap_walk_anon+0x4f6/0x770 unmap_folio+0x196/0x1f0 split_huge_page_to_list_to_order+0x9f6/0x1560 deferred_split_scan+0xac5/0x12a0 shrinker_debugfs_scan_write+0x376/0x470 full_proxy_write+0x15c/0x220 vfs_write+0x2fc/0xcb0 ksys_write+0x146/0x250 do_syscall_64+0x6a/0x120 entry_SYSCALL_64_after_hwframe+0x76/0x7e The bug is found by syzkaller on an internal kernel, then confirmed on upstream.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

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

Problem Types: CWE-476

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 753f142f7ff7d2223a47105b61e1efd91587d711 git Not specified
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 9468afbda3fbfcec21ac8132364dff3dab945faf git Not specified
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 ef5706bed97e240b4abf4233ceb03da7336bc775 git Not specified
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 22f6368768340260e862f35151d2e1c55cb1dc75 git Not specified
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 3977946f61cdba87b6b5aaf7d7094e96089583a5 git Not specified
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 6166c3cf405441f7147b322980144feb3cefc617 git Not specified
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 fbab262b0c8226c697af1851a424896ed47dedcc git Not specified
CNA Linux Linux affected 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 be6e843fc51a584672dfd9c4a6a24c8cb81d5fb7 git Not specified
CNA Linux Linux affected 4.14 Not specified
CNA Linux Linux unaffected 4.14 semver Not specified
CNA Linux Linux unaffected 5.4.295 5.4.* semver Not specified
CNA Linux Linux unaffected 5.10.239 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.186 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.142 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.95 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.29 6.12.* semver Not specified
CNA Linux Linux unaffected 6.14.7 6.14.* semver Not specified
CNA Linux Linux unaffected 6.15 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
lists.debian.org/debian-lts-announce/2025/10/msg00008.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Third Party Advisory
git.kernel.org/stable/c/22f6368768340260e862f35151d2e1c55cb1dc75 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/fbab262b0c8226c697af1851a424896ed47dedcc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/be6e843fc51a584672dfd9c4a6a24c8cb81d5fb7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/ef5706bed97e240b4abf4233ceb03da7336bc775 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/753f142f7ff7d2223a47105b61e1efd91587d711 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/9468afbda3fbfcec21ac8132364dff3dab945faf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/3977946f61cdba87b6b5aaf7d7094e96089583a5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/6166c3cf405441f7147b322980144feb3cefc617 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
lists.debian.org/debian-lts-announce/2025/10/msg00007.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Third Party Advisory
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