Vulnerability-Lookup

GHSA-H283-RR2H-W2JJ

Vulnerability from github – Published: 2025-10-01 09:30 – Updated: 2025-12-12 21:31

Details

In the Linux kernel, the following vulnerability has been resolved:

mm/userfaultfd: fix kmap_local LIFO ordering for CONFIG_HIGHPTE

With CONFIG_HIGHPTE on 32-bit ARM, move_pages_pte() maps PTE pages using kmap_local_page(), which requires unmapping in Last-In-First-Out order.

The current code maps dst_pte first, then src_pte, but unmaps them in the same order (dst_pte, src_pte), violating the LIFO requirement. This causes the warning in kunmap_local_indexed():

WARNING: CPU: 0 PID: 604 at mm/highmem.c:622 kunmap_local_indexed+0x178/0x17c addr != __fix_to_virt(FIX_KMAP_BEGIN + idx)

Fix this by reversing the unmap order to respect LIFO ordering.

This issue follows the same pattern as similar fixes: - commit eca6828403b8 ("crypto: skcipher - fix mismatch between mapping and unmapping order") - commit 8cf57c6df818 ("nilfs2: eliminate staggered calls to kunmap in nilfs_rename")

Both of which addressed the same fundamental requirement that kmap_local operations must follow LIFO ordering.

Severity

5.5 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2025-39899"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-10-01T08:15:32Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/userfaultfd: fix kmap_local LIFO ordering for CONFIG_HIGHPTE\n\nWith CONFIG_HIGHPTE on 32-bit ARM, move_pages_pte() maps PTE pages using\nkmap_local_page(), which requires unmapping in Last-In-First-Out order.\n\nThe current code maps dst_pte first, then src_pte, but unmaps them in the\nsame order (dst_pte, src_pte), violating the LIFO requirement.  This\ncauses the warning in kunmap_local_indexed():\n\n  WARNING: CPU: 0 PID: 604 at mm/highmem.c:622 kunmap_local_indexed+0x178/0x17c\n  addr \\!= __fix_to_virt(FIX_KMAP_BEGIN + idx)\n\nFix this by reversing the unmap order to respect LIFO ordering.\n\nThis issue follows the same pattern as similar fixes:\n- commit eca6828403b8 (\"crypto: skcipher - fix mismatch between mapping and unmapping order\")\n- commit 8cf57c6df818 (\"nilfs2: eliminate staggered calls to kunmap in nilfs_rename\")\n\nBoth of which addressed the same fundamental requirement that kmap_local\noperations must follow LIFO ordering.",
  "id": "GHSA-h283-rr2h-w2jj",
  "modified": "2025-12-12T21:31:33Z",
  "published": "2025-10-01T09:30:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39899"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9614d8bee66387501f48718fa306e17f2aa3f2f3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b051f707018967ea8f697d790a1ed8c443f63812"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bd1ee62759d0bd4d6b909731c076c230ac89d61e"
    }
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  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-39899 (GCVE-0-2025-39899)

Vulnerability from cvelistv5 – Published: 2025-10-01 07:42 – Updated: 2026-05-11 21:38

Title

mm/userfaultfd: fix kmap_local LIFO ordering for CONFIG_HIGHPTE

Summary

In the Linux kernel, the following vulnerability has been resolved: mm/userfaultfd: fix kmap_local LIFO ordering for CONFIG_HIGHPTE With CONFIG_HIGHPTE on 32-bit ARM, move_pages_pte() maps PTE pages using kmap_local_page(), which requires unmapping in Last-In-First-Out order. The current code maps dst_pte first, then src_pte, but unmaps them in the same order (dst_pte, src_pte), violating the LIFO requirement. This causes the warning in kunmap_local_indexed(): WARNING: CPU: 0 PID: 604 at mm/highmem.c:622 kunmap_local_indexed+0x178/0x17c addr \!= __fix_to_virt(FIX_KMAP_BEGIN + idx) Fix this by reversing the unmap order to respect LIFO ordering. This issue follows the same pattern as similar fixes: - commit eca6828403b8 ("crypto: skcipher - fix mismatch between mapping and unmapping order") - commit 8cf57c6df818 ("nilfs2: eliminate staggered calls to kunmap in nilfs_rename") Both of which addressed the same fundamental requirement that kmap_local operations must follow LIFO ordering.

Severity

5.5 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-01-14 19:29 UTC

CWE

CWE-noinfo Not enough information

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/b051f707018967ea8…
https://git.kernel.org/stable/c/bd1ee62759d0bd4d6…
https://git.kernel.org/stable/c/9614d8bee66387501…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: adef440691bab824e39c1b17382322d195e1fab0 , < b051f707018967ea8f697d790a1ed8c443f63812 (git) Affected: adef440691bab824e39c1b17382322d195e1fab0 , < bd1ee62759d0bd4d6b909731c076c230ac89d61e (git) Affected: adef440691bab824e39c1b17382322d195e1fab0 , < 9614d8bee66387501f48718fa306e17f2aa3f2f3 (git)
Linux	Linux	Affected: 6.8 Unaffected: 0 , < 6.8 (semver) Unaffected: 6.12.46 , ≤ 6.12.* (semver) Unaffected: 6.16.6 , ≤ 6.16.* (semver) Unaffected: 6.17 , ≤ * (original_commit_for_fix)

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              "attackComplexity": "LOW",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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