FKIE_CVE-2026-43188

Vulnerability from fkie_nvd - Published: 2026-05-06 12:16 - Updated: 2026-05-11 20:38
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: ceph: do not propagate page array emplacement errors as batch errors When fscrypt is enabled, move_dirty_folio_in_page_array() may fail because it needs to allocate bounce buffers to store the encrypted versions of each folio. Each folio beyond the first allocates its bounce buffer with GFP_NOWAIT. Failures are common (and expected) under this allocation mode; they should flush (not abort) the batch. However, ceph_process_folio_batch() uses the same `rc` variable for its own return code and for capturing the return codes of its routine calls; failing to reset `rc` back to 0 results in the error being propagated out to the main writeback loop, which cannot actually tolerate any errors here: once `ceph_wbc.pages` is allocated, it must be passed to ceph_submit_write() to be freed. If it survives until the next iteration (e.g. due to the goto being followed), ceph_allocate_page_array()'s BUG_ON() will oops the worker. Note that this failure mode is currently masked due to another bug (addressed next in this series) that prevents multiple encrypted folios from being selected for the same write. For now, just reset `rc` when redirtying the folio to prevent errors in move_dirty_folio_in_page_array() from propagating. Note that move_dirty_folio_in_page_array() is careful never to return errors on the first folio, so there is no need to check for that. After this change, ceph_process_folio_batch() no longer returns errors; its only remaining failure indicator is `locked_pages == 0`, which the caller already handles correctly.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4c0d84c788d89c167abf0bf84fd37890c4c84f08Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/707104682e3c163f7c14cdd6b07a3e95fb374759Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/746840c87d76b614b14d9337c466ff022fc49823Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: do not propagate page array emplacement errors as batch errors\n\nWhen fscrypt is enabled, move_dirty_folio_in_page_array() may fail\nbecause it needs to allocate bounce buffers to store the encrypted\nversions of each folio. Each folio beyond the first allocates its bounce\nbuffer with GFP_NOWAIT. Failures are common (and expected) under this\nallocation mode; they should flush (not abort) the batch.\n\nHowever, ceph_process_folio_batch() uses the same `rc` variable for its\nown return code and for capturing the return codes of its routine calls;\nfailing to reset `rc` back to 0 results in the error being propagated\nout to the main writeback loop, which cannot actually tolerate any\nerrors here: once `ceph_wbc.pages` is allocated, it must be passed to\nceph_submit_write() to be freed. If it survives until the next iteration\n(e.g. due to the goto being followed), ceph_allocate_page_array()\u0027s\nBUG_ON() will oops the worker.\n\nNote that this failure mode is currently masked due to another bug\n(addressed next in this series) that prevents multiple encrypted folios\nfrom being selected for the same write.\n\nFor now, just reset `rc` when redirtying the folio to prevent errors in\nmove_dirty_folio_in_page_array() from propagating. Note that\nmove_dirty_folio_in_page_array() is careful never to return errors on\nthe first folio, so there is no need to check for that. After this\nchange, ceph_process_folio_batch() no longer returns errors; its only\nremaining failure indicator is `locked_pages == 0`, which the caller\nalready handles correctly."
    }
  ],
  "id": "CVE-2026-43188",
  "lastModified": "2026-05-11T20:38:38.500",
  "metrics": {
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "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",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
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  "published": "2026-05-06T12:16:37.600",
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  "vulnStatus": "Analyzed",
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          "value": "NVD-CWE-noinfo"
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      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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