CriticalFix available

ocfs2/dlm: validate qr_numregions in dlm_match_regions()

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: ocfs2/dlm: validate qr_numregions in dlm_match_regions() Patch series "ocfs2/dlm: fix two bugs in dlm_match_regions()". In dlm_match_regions(), the qr_numregions field from a DLM_QUERY_REGION network message is used to drive loops over the qr_regions buffer without sufficient validation. This series fixes two issues: - Patch 1 adds a bounds check to reject messages where qr_numregions exceeds O2NM_MAX_REGIONS. The o2net layer only validates message byte length; it does not constrain field values, so a crafted message can set qr_numregions up to 255 and trigger out-of-bounds reads past the 1024-byte qr_regions buffer. - Patch 2 fixes an off-by-one in the local-vs-remote comparison loop, which uses '<=' instead of '<', reading one entry past the valid range even when qr_numregions is within bounds. This patch (of 2): The qr_numregions field from a DLM_QUERY_REGION network message is used directly as loop bounds in dlm_match_regions() without checking against O2NM_MAX_REGIONS. Since qr_regions is sized for at most O2NM_MAX_REGIONS (32) entries, a crafted message with qr_numregions > 32 causes out-of-bounds reads past the qr_regions buffer. Add a bounds check for qr_numregions before entering the loops.

Products: Kernel
Affected versions: Not specified
Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.12.91, 6.18.33, 6.6.141, 7.0.10
CVEs: CVE-2026-53043
Confirmed fixed CVEs: Not specified
Updated in this feed: 2 Nov 2026, 21:45 UTC · Revision 1

Source evidence

ocfs2/dlm: validate qr_numregions in dlm_match_regions()

core-osv · Original source

Published 24 Jun 2026, 16:29 UTC

osv:CVE-2026-53043

Kernel

Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10

Complete source record

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  "url": "https://osv.dev/vulnerability/CVE-2026-53043",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ocfs2/dlm: validate qr_numregions in dlm_match_regions()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ocfs2/dlm: validate qr_numregions in dlm_match_regions() Patch series \"ocfs2/dlm: fix two bugs in dlm_match_regions()\". In dlm_match_regions(), the qr_numregions field from a DLM_QUERY_REGION network message is used to drive loops over the qr_regions buffer without sufficient validation. This series fixes two issues: - Patch 1 adds a bounds check to reject messages where qr_numregions exceeds O2NM_MAX_REGIONS. The o2net layer only validates message byte length; it does not constrain field values, so a crafted message can set qr_numregions up to 255 and trigger out-of-bounds reads past the 1024-byte qr_regions buffer. - Patch 2 fixes an off-by-one in the local-vs-remote comparison loop, which uses '<=' instead of '<', reading one entry past the valid range even when qr_numregions is within bounds. This patch (of 2): The qr_numregions field from a DLM_QUERY_REGION network message is used directly as loop bounds in dlm_match_regions() without checking against O2NM_MAX_REGIONS. Since qr_regions is sized for at most O2NM_MAX_REGIONS (32) entries, a crafted message with qr_numregions > 32 causes out-of-bounds reads past the qr_regions buffer. Add a bounds check for qr_numregions before entering the loops.",
    "evidence": "osv:CVE-2026-53043",
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      "modified": "2026-10-28T02:30:24.182819113Z",
      "provider": "osv",
      "references": [
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        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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  "source_id": "core-osv",
  "document_id": 490338,
  "published_at": "2026-06-24T16:29:49.48+00:00"
}