FKIE_CVE-2026-43127

Vulnerability from fkie_nvd - Published: 2026-05-06 12:16 - Updated: 2026-05-08 17:54
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ntfs3: fix circular locking dependency in run_unpack_ex Syzbot reported a circular locking dependency between wnd->rw_lock (sbi->used.bitmap) and ni->file.run_lock. The deadlock scenario: 1. ntfs_extend_mft() takes ni->file.run_lock then wnd->rw_lock. 2. run_unpack_ex() takes wnd->rw_lock then tries to acquire ni->file.run_lock inside ntfs_refresh_zone(). This creates an AB-BA deadlock. Fix this by using down_read_trylock() instead of down_read() when acquiring run_lock in run_unpack_ex(). If the lock is contended, skip ntfs_refresh_zone() - the MFT zone will be refreshed on the next MFT operation. This breaks the circular dependency since we never block waiting for run_lock while holding wnd->rw_lock.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/08ce2fee1b869ecbfbd94e0eb2630e52203a2e03Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b014372b62237521444ee51384549bdf48b79015Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b8d22d9d8260b0f4f4d8e2898c98037c9982ea66Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
To clipboard 

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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: fix circular locking dependency in run_unpack_ex\n\nSyzbot reported a circular locking dependency between wnd-\u003erw_lock\n(sbi-\u003eused.bitmap) and ni-\u003efile.run_lock.\n\nThe deadlock scenario:\n1. ntfs_extend_mft() takes ni-\u003efile.run_lock then wnd-\u003erw_lock.\n2. run_unpack_ex() takes wnd-\u003erw_lock then tries to acquire\n   ni-\u003efile.run_lock inside ntfs_refresh_zone().\n\nThis creates an AB-BA deadlock.\n\nFix this by using down_read_trylock() instead of down_read() when\nacquiring run_lock in run_unpack_ex(). If the lock is contended,\nskip ntfs_refresh_zone() - the MFT zone will be refreshed on the\nnext MFT operation. This breaks the circular dependency since we\nnever block waiting for run_lock while holding wnd-\u003erw_lock."
    }
  ],
  "id": "CVE-2026-43127",
  "lastModified": "2026-05-08T17:54:46.340",
  "metrics": {
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          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
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          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
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  "published": "2026-05-06T12:16:29.727",
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