{"id":"CVE-2026-53043","summary":"ocfs2/dlm: validate qr_numregions in dlm_match_regions()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2/dlm: validate qr_numregions in dlm_match_regions()\n\nPatch series \"ocfs2/dlm: fix two bugs in dlm_match_regions()\".\n\nIn dlm_match_regions(), the qr_numregions field from a DLM_QUERY_REGION\nnetwork message is used to drive loops over the qr_regions buffer without\nsufficient validation.  This series fixes two issues:\n\n- Patch 1 adds a bounds check to reject messages where qr_numregions\n  exceeds O2NM_MAX_REGIONS. The o2net layer only validates message\n  byte length; it does not constrain field values, so a crafted message\n  can set qr_numregions up to 255 and trigger out-of-bounds reads past\n  the 1024-byte qr_regions buffer.\n\n- Patch 2 fixes an off-by-one in the local-vs-remote comparison loop,\n  which uses '\u003c=' instead of '\u003c', reading one entry past the valid range\n  even when qr_numregions is within bounds.\n\n\nThis patch (of 2):\n\nThe qr_numregions field from a DLM_QUERY_REGION network message is used\ndirectly as loop bounds in dlm_match_regions() without checking against\nO2NM_MAX_REGIONS.  Since qr_regions is sized for at most O2NM_MAX_REGIONS\n(32) entries, a crafted message with qr_numregions \u003e 32 causes\nout-of-bounds reads past the qr_regions buffer.\n\nAdd a bounds check for qr_numregions before entering the loops.","modified":"2026-07-08T08:09:45.151050252Z","published":"2026-06-24T16:29:49.480Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53043.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1f8b91275912cd428289c1fb424bebd7ff5302bd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3c2d0de23ae4be22b6c18e8f0915be74d3b5fb21"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3f474c33ebc2e2ca3fcb587d7de4375348f13373"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6c6e8fc3c007319981647b410c29bb5775048551"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7ab3fbb01bc6d79091bc375e5235d360cd9b78be"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d3d5efade0c79dac1cac98c0cb1115432f804439"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f37de46149db49abd2b24f4f0c5a88cf4dfb5f47"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f69551139caf6d24242a0ad049ee46b264e3aee0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53043.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53043"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ea2034416b54700e30371f2ad6517cbb94674083"},{"fixed":"d3d5efade0c79dac1cac98c0cb1115432f804439"},{"fixed":"f69551139caf6d24242a0ad049ee46b264e3aee0"},{"fixed":"1f8b91275912cd428289c1fb424bebd7ff5302bd"},{"fixed":"f37de46149db49abd2b24f4f0c5a88cf4dfb5f47"},{"fixed":"6c6e8fc3c007319981647b410c29bb5775048551"},{"fixed":"3f474c33ebc2e2ca3fcb587d7de4375348f13373"},{"fixed":"3c2d0de23ae4be22b6c18e8f0915be74d3b5fb21"},{"fixed":"7ab3fbb01bc6d79091bc375e5235d360cd9b78be"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53043.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.37"},{"fixed":"5.10.258"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.209"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.141"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.91"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.33"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53043.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"}]}