{"api_version":"1","generated_at":"2026-09-12T04:00:30+00:00","cve":"CVE-2026-89495","urls":{"html":"https://cve.report/CVE-2026-89495","api":"https://cve.report/api/cve/CVE-2026-89495.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89495","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89495"},"summary":{"title":"ocfs2: bound namelen in dlm_migrate_request_handler","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: bound namelen in dlm_migrate_request_handler\n\nPatch series \"ocfs2/dlm: bound peer-controlled lengths in the o2dlm\".\n\nThe o2dlm receive handlers trust u8 length and count fields from the wire\nwithout bounding them, so a node in a DLM domain can corrupt or panic any\nother node with a malformed message.  Three defects:\n\n  - dlm_migrate_request_handler() passes migrate->namelen unchecked to\n    dlm_init_mle(), which memcpy()s it into the 32-byte mname[] of an\n    o2dlm_mle slab object: a heap out-of-bounds write of up to ~215\n    attacker-controlled bytes.\n\n  - dlm_mig_lockres_handler() passes mres->lockname_len unchecked to\n    dlm_init_lockres(), which memcpy()s it into the 32-byte o2dlm_lockname\n    slab object: a heap out-of-bounds write of up to ~223 bytes.\n\n  - the same handler trusts mres->num_locks without checking that the\n    message is large enough to hold that many entries, so\n    dlm_process_recovery_data() walks mres->ml[] past the kmalloc(data_len)\n    copy and trips a BUG_ON (an out-of-bounds read ending in a panic).\n\nThe other o2dlm receive handlers already reject an oversized name; the\nmigration and recovery handlers have omitted it since the DLM was added\n(see the Fixes tags).  Patch 1 bounds namelen; patch 2 validates\nlockname_len, num_locks, and the payload size.  Conforming recovery and\nmigration traffic is unaffected.\n\no2net authenticates peers only by the DLM domain key, so any node that has\njoined the domain -- including a compromised or malicious member -- can\nsend these messages.  There is no local trigger; the attacker must already\nbe a member of the cluster.\n\nEach sink was confirmed under KASAN with an out-of-tree module mirroring\nit exactly -- a kmem_cache/kmalloc of the real destination size, then the\nsame unclamped memcpy/loop: slab-out-of-bounds Write for the two writes,\nRead for the recovery walk, and a panic.  A userspace AddressSanitizer\nbuild faults identically under -m32 and -m64.  Scrubbed logs are available\non request.\n\nI reported this privately to security@kernel.org and the ocfs2 maintainers\non 2026-06-20; with no response after the standard embargo period I am\nposting the fix publicly.  I have no embargo requirement.\n\n\nThis patch (of 2):\n\nA node receiving a DLM_MIGRATE_REQUEST message trusts the peer-supplied\nname length (migrate->namelen) without bounding it.  dlm_init_mle() then\ncopies that many bytes into the fixed DLM_LOCKID_NAME_MAX-byte mname[]\narray of an o2dlm_mle slab object, so a malformed message from a cluster\npeer overflows the slab object by up to ~215 bytes: a heap out-of-bounds\nwrite of attacker-controlled data, reachable by any node in the domain.\n\nReject an oversized name, the way dlm_master_request_handler() and the\nother o2dlm receive handlers already do; the migration handler omits the\ncheck entirely.  Conforming messages are unaffected.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:31","updated_at":"2026-09-11 20:19:31"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/de10cd3b062a5235af754925fcf49beb5a1109d4","name":"https://git.kernel.org/stable/c/de10cd3b062a5235af754925fcf49beb5a1109d4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f8658ee3327f73bd81c0bcd07cdeb5a8527fac98","name":"https://git.kernel.org/stable/c/f8658ee3327f73bd81c0bcd07cdeb5a8527fac98","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2487bea2098322669f0563baff53e797486b823f","name":"https://git.kernel.org/stable/c/2487bea2098322669f0563baff53e797486b823f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ea5b5609305a8437bc955a0834a530c12246d78f","name":"https://git.kernel.org/stable/c/ea5b5609305a8437bc955a0834a530c12246d78f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89495","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89495","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6714d8e86bf443f6f7af50f9d432025649f091f5 f8658ee3327f73bd81c0bcd07cdeb5a8527fac98 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6714d8e86bf443f6f7af50f9d432025649f091f5 de10cd3b062a5235af754925fcf49beb5a1109d4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6714d8e86bf443f6f7af50f9d432025649f091f5 2487bea2098322669f0563baff53e797486b823f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6714d8e86bf443f6f7af50f9d432025649f091f5 ea5b5609305a8437bc955a0834a530c12246d78f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.16","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/ocfs2/dlm/dlmmaster.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"f8658ee3327f73bd81c0bcd07cdeb5a8527fac98","status":"affected","version":"6714d8e86bf443f6f7af50f9d432025649f091f5","versionType":"git"},{"lessThan":"de10cd3b062a5235af754925fcf49beb5a1109d4","status":"affected","version":"6714d8e86bf443f6f7af50f9d432025649f091f5","versionType":"git"},{"lessThan":"2487bea2098322669f0563baff53e797486b823f","status":"affected","version":"6714d8e86bf443f6f7af50f9d432025649f091f5","versionType":"git"},{"lessThan":"ea5b5609305a8437bc955a0834a530c12246d78f","status":"affected","version":"6714d8e86bf443f6f7af50f9d432025649f091f5","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/ocfs2/dlm/dlmmaster.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.16"},{"lessThan":"2.6.16","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.109","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"2.6.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"2.6.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"2.6.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"2.6.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: bound namelen in dlm_migrate_request_handler\n\nPatch series \"ocfs2/dlm: bound peer-controlled lengths in the o2dlm\".\n\nThe o2dlm receive handlers trust u8 length and count fields from the wire\nwithout bounding them, so a node in a DLM domain can corrupt or panic any\nother node with a malformed message.  Three defects:\n\n  - dlm_migrate_request_handler() passes migrate->namelen unchecked to\n    dlm_init_mle(), which memcpy()s it into the 32-byte mname[] of an\n    o2dlm_mle slab object: a heap out-of-bounds write of up to ~215\n    attacker-controlled bytes.\n\n  - dlm_mig_lockres_handler() passes mres->lockname_len unchecked to\n    dlm_init_lockres(), which memcpy()s it into the 32-byte o2dlm_lockname\n    slab object: a heap out-of-bounds write of up to ~223 bytes.\n\n  - the same handler trusts mres->num_locks without checking that the\n    message is large enough to hold that many entries, so\n    dlm_process_recovery_data() walks mres->ml[] past the kmalloc(data_len)\n    copy and trips a BUG_ON (an out-of-bounds read ending in a panic).\n\nThe other o2dlm receive handlers already reject an oversized name; the\nmigration and recovery handlers have omitted it since the DLM was added\n(see the Fixes tags).  Patch 1 bounds namelen; patch 2 validates\nlockname_len, num_locks, and the payload size.  Conforming recovery and\nmigration traffic is unaffected.\n\no2net authenticates peers only by the DLM domain key, so any node that has\njoined the domain -- including a compromised or malicious member -- can\nsend these messages.  There is no local trigger; the attacker must already\nbe a member of the cluster.\n\nEach sink was confirmed under KASAN with an out-of-tree module mirroring\nit exactly -- a kmem_cache/kmalloc of the real destination size, then the\nsame unclamped memcpy/loop: slab-out-of-bounds Write for the two writes,\nRead for the recovery walk, and a panic.  A userspace AddressSanitizer\nbuild faults identically under -m32 and -m64.  Scrubbed logs are available\non request.\n\nI reported this privately to security@kernel.org and the ocfs2 maintainers\non 2026-06-20; with no response after the standard embargo period I am\nposting the fix publicly.  I have no embargo requirement.\n\n\nThis patch (of 2):\n\nA node receiving a DLM_MIGRATE_REQUEST message trusts the peer-supplied\nname length (migrate->namelen) without bounding it.  dlm_init_mle() then\ncopies that many bytes into the fixed DLM_LOCKID_NAME_MAX-byte mname[]\narray of an o2dlm_mle slab object, so a malformed message from a cluster\npeer overflows the slab object by up to ~215 bytes: a heap out-of-bounds\nwrite of attacker-controlled data, reachable by any node in the domain.\n\nReject an oversized name, the way dlm_master_request_handler() and the\nother o2dlm receive handlers already do; the migration handler omits the\ncheck entirely.  Conforming messages are unaffected."}],"providerMetadata":{"dateUpdated":"2026-09-11T19:43:46.107Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/f8658ee3327f73bd81c0bcd07cdeb5a8527fac98"},{"url":"https://git.kernel.org/stable/c/de10cd3b062a5235af754925fcf49beb5a1109d4"},{"url":"https://git.kernel.org/stable/c/2487bea2098322669f0563baff53e797486b823f"},{"url":"https://git.kernel.org/stable/c/ea5b5609305a8437bc955a0834a530c12246d78f"}],"title":"ocfs2: bound namelen in dlm_migrate_request_handler","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89495","datePublished":"2026-09-11T19:43:46.107Z","dateReserved":"2026-09-11T19:38:34.714Z","dateUpdated":"2026-09-11T19:43:46.107Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:31","lastModifiedDate":"2026-09-11 20:19:31","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89495","Ordinal":"1","Title":"ocfs2: bound namelen in dlm_migrate_request_handler","CVE":"CVE-2026-89495","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89495","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: bound namelen in dlm_migrate_request_handler\n\nPatch series \"ocfs2/dlm: bound peer-controlled lengths in the o2dlm\".\n\nThe o2dlm receive handlers trust u8 length and count fields from the wire\nwithout bounding them, so a node in a DLM domain can corrupt or panic any\nother node with a malformed message.  Three defects:\n\n  - dlm_migrate_request_handler() passes migrate->namelen unchecked to\n    dlm_init_mle(), which memcpy()s it into the 32-byte mname[] of an\n    o2dlm_mle slab object: a heap out-of-bounds write of up to ~215\n    attacker-controlled bytes.\n\n  - dlm_mig_lockres_handler() passes mres->lockname_len unchecked to\n    dlm_init_lockres(), which memcpy()s it into the 32-byte o2dlm_lockname\n    slab object: a heap out-of-bounds write of up to ~223 bytes.\n\n  - the same handler trusts mres->num_locks without checking that the\n    message is large enough to hold that many entries, so\n    dlm_process_recovery_data() walks mres->ml[] past the kmalloc(data_len)\n    copy and trips a BUG_ON (an out-of-bounds read ending in a panic).\n\nThe other o2dlm receive handlers already reject an oversized name; the\nmigration and recovery handlers have omitted it since the DLM was added\n(see the Fixes tags).  Patch 1 bounds namelen; patch 2 validates\nlockname_len, num_locks, and the payload size.  Conforming recovery and\nmigration traffic is unaffected.\n\no2net authenticates peers only by the DLM domain key, so any node that has\njoined the domain -- including a compromised or malicious member -- can\nsend these messages.  There is no local trigger; the attacker must already\nbe a member of the cluster.\n\nEach sink was confirmed under KASAN with an out-of-tree module mirroring\nit exactly -- a kmem_cache/kmalloc of the real destination size, then the\nsame unclamped memcpy/loop: slab-out-of-bounds Write for the two writes,\nRead for the recovery walk, and a panic.  A userspace AddressSanitizer\nbuild faults identically under -m32 and -m64.  Scrubbed logs are available\non request.\n\nI reported this privately to security@kernel.org and the ocfs2 maintainers\non 2026-06-20; with no response after the standard embargo period I am\nposting the fix publicly.  I have no embargo requirement.\n\n\nThis patch (of 2):\n\nA node receiving a DLM_MIGRATE_REQUEST message trusts the peer-supplied\nname length (migrate->namelen) without bounding it.  dlm_init_mle() then\ncopies that many bytes into the fixed DLM_LOCKID_NAME_MAX-byte mname[]\narray of an o2dlm_mle slab object, so a malformed message from a cluster\npeer overflows the slab object by up to ~215 bytes: a heap out-of-bounds\nwrite of attacker-controlled data, reachable by any node in the domain.\n\nReject an oversized name, the way dlm_master_request_handler() and the\nother o2dlm receive handlers already do; the migration handler omits the\ncheck entirely.  Conforming messages are unaffected.","Type":"Description","Title":"ocfs2: bound namelen in dlm_migrate_request_handler"}]}}}