CVE-2026-72381

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-72381", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.923Z", "datePublished": "2026-08-15T05:56:13.477Z", "dateUpdated": "2026-08-17T05:43:32.020Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:43:32.020Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free of fp->owner.name in durable handle owner check\n\nTwo concurrent SMB2 durable reconnects (DH2C/DHnC) on the same\npersistent_id race the fp->owner.name compare-read in\nksmbd_vfs_compare_durable_owner() against the kfree() in\nksmbd_reopen_durable_fd()'s reopen-success path. fp->owner.name is a\nstandalone kstrdup() buffer whose lifetime is independent of the fp\nrefcount, and the two sites share no lock: the compare reads the buffer\nwhile the reopen frees it, so the strcmp() can dereference freed memory.\n\nCommit 7ce4fc40018d (\"ksmbd: fix durable reconnect double-bind race in\nksmbd_reopen_durable_fd\") made the fp->conn claim atomic under\nglobal_ft.lock (closing the owner.name double-free and the ksmbd_file\nwrite-UAF), but the compare-read versus reopen-free pair was left\nunserialized.\n\n BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80\n Read of size 1 by task kworker\n strcmp\n ksmbd_vfs_compare_durable_owner\n smb2_check_durable_oplock\n smb2_open\n Freed by task kworker:\n kfree\n ksmbd_reopen_durable_fd\n smb2_open\n Allocated by task kworker:\n kstrdup\n session_fd_check\n smb2_session_logoff\n The buggy address belongs to the cache kmalloc-8\n\nSerialize both sides of the race with fp->f_lock. The global durable\nfile-table lock still protects the durable reconnect claim, but\nfp->owner.name is per-open state and does not need to block unrelated\ndurable table lookups or reconnects. The teardown is left at its\nexisting location after the reopen-success point so that an __open_id()\nrollback still retains owner.name for a later legitimate reconnect to\nverify."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The flaw is reached via ksmbd's in-kernel SMB2 server on TCP port 445; remote SMB2_CREATE durable-handle reconnect packets (DH2C/DHnC) traverse ksmbd_conn_handler_loop() -> smb2_check_user_session() -> smb2_open() -> parse_durable_handle_context() -> smb2_check_durable_oplock() / ksmbd_reopen_durable_fd().\nAC:L - The attacker controls both sides of the race by opening a durable handle, issuing SMB2_LOGOFF to preserve owner.name via session_fd_check(), then sending concurrent SMB2_CREATE durable reconnect requests for the same persistent_id from multiple connections; no timing or layout outside attacker control is required.\nPR:N - Exploitation requires only network reachability to ksmbd and valid SMB session credentials (guest or any share user) plus tree connect; no elevated host privileges, capabilities, or local access are needed beyond share-level SMB access obtainable through the protocol itself.\nUI:N - No victim user interaction is required beyond a server running ksmbd with durable handles enabled; the attacker programmatically drives the open, logoff, and concurrent reconnect SMB2 sequence over the network.\nS:U - Impact is confined to kernel heap memory corruption and privilege escalation within the same host security authority; this is not a VM escape, container boundary bypass, or IOMMU/DMA isolation break.\nC:H - strcmp() in ksmbd_vfs_compare_durable_owner() dereferences a freed kmalloc-8 fp->owner.name buffer while a concurrent ksmbd_reopen_durable_fd() kfree() runs; this slab use-after-free enables arbitrary kernel memory disclosure via heap reuse.\nI:H - Use-after-free of the standalone owner.name kstrdup buffer provides kernel heap corruption primitives; with heap grooming the freed slab can be reallocated for arbitrary kernel memory writes and control-flow hijacking.\nA:H - KASAN reports slab-use-after-free in strcmp on the owner.name buffer during concurrent smb2_open durable reconnects; the UAF can trigger kernel oops or panic on ksmbd worker threads and is repeatable by resending concurrent reconnect requests."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/vfs_cache.c"], "versions": [{"version": "712cdf917e77a6444ce3836874829d770db20ee6", "lessThan": "fb978d72052704c6b06c6b0f129fcd60b77169f5", "status": "affected", "versionType": "git"}, {"version": "c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d", "lessThan": "93d4d46bf9d442a12ea87278049ec416962c627f", "status": "affected", "versionType": "git"}, {"version": "00ce8d6789dae72d042a4522264964c72891ca37", "lessThan": "5a5ac2852cd326529d02f778bc1aa6184701f4d7", "status": "affected", "versionType": "git"}, {"version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a", "lessThan": "ed98719be41389d416953b8ef9f07a07dfea6b2b", "status": "affected", "versionType": "git"}, {"version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a", "lessThan": "38637163501fd9e2f684b8cd275d0db5d79f37c6", "status": "affected", "versionType": "git"}, {"version": "c908c853f304a4969b5aa10eba0b50350cc65b80", "status": "affected", "versionType": "git"}, {"version": "6.6.142", "lessThan": "6.6.145", "status": "affected", "versionType": "semver"}, {"version": "6.12.92", "lessThan": "6.12.97", "status": "affected", "versionType": "semver"}, {"version": "6.18.25", "lessThan": "6.18.40", "status": "affected", "versionType": "semver"}, {"version": "7.0.2", "lessThan": "7.1", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/vfs_cache.c"], "versions": [{"version": "7.1", "status": "affected"}, {"version": "0", "lessThan": "7.1", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.142", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.92", "versionEndExcluding": "6.12.97"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.25", "versionEndExcluding": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/fb978d72052704c6b06c6b0f129fcd60b77169f5"}, {"url": "https://git.kernel.org/stable/c/93d4d46bf9d442a12ea87278049ec416962c627f"}, {"url": "https://git.kernel.org/stable/c/5a5ac2852cd326529d02f778bc1aa6184701f4d7"}, {"url": "https://git.kernel.org/stable/c/ed98719be41389d416953b8ef9f07a07dfea6b2b"}, {"url": "https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6"}], "title": "ksmbd: fix use-after-free of fp->owner.name in durable handle owner check", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/server/vfs_cache.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "fb978d72052704c6b06c6b0f129fcd60b77169f5", "status": "affected", "version": "712cdf917e77a6444ce3836874829d770db20ee6", "versionType": "git"}, {"lessThan": "93d4d46bf9d442a12ea87278049ec416962c627f", "status": "affected", "version": "c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d", "versionType": "git"}, {"lessThan": "5a5ac2852cd326529d02f778bc1aa6184701f4d7", "status": "affected", "version": "00ce8d6789dae72d042a4522264964c72891ca37", "versionType": "git"}, {"lessThan": "ed98719be41389d416953b8ef9f07a07dfea6b2b", "status": "affected", "version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a", "versionType": "git"}, {"lessThan": "38637163501fd9e2f684b8cd275d0db5d79f37c6", "status": "affected", "version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a", "versionType": "git"}, {"status": "affected", "version": "c908c853f304a4969b5aa10eba0b50350cc65b80", "versionType": "git"}, {"lessThan": "6.6.145", "status": "affected", "version": "6.6.142", "versionType": "semver"}, {"lessThan": "6.12.97", "status": "affected", "version": "6.12.92", "versionType": "semver"}, {"lessThan": "6.18.40", "status": "affected", "version": "6.18.25", "versionType": "semver"}, {"lessThan": "7.1", "status": "affected", "version": "7.0.2", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/server/vfs_cache.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "7.1"}, {"lessThan": "7.1", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.145", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.97", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.40", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.5", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free of fp->owner.name in durable handle owner check\n\nTwo concurrent SMB2 durable reconnects (DH2C/DHnC) on the same\npersistent_id race the fp->owner.name compare-read in\nksmbd_vfs_compare_durable_owner() against the kfree() in\nksmbd_reopen_durable_fd()'s reopen-success path. fp->owner.name is a\nstandalone kstrdup() buffer whose lifetime is independent of the fp\nrefcount, and the two sites share no lock: the compare reads the buffer\nwhile the reopen frees it, so the strcmp() can dereference freed memory.\n\nCommit 7ce4fc40018d (\"ksmbd: fix durable reconnect double-bind race in\nksmbd_reopen_durable_fd\") made the fp->conn claim atomic under\nglobal_ft.lock (closing the owner.name double-free and the ksmbd_file\nwrite-UAF), but the compare-read versus reopen-free pair was left\nunserialized.\n\n BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80\n Read of size 1 by task kworker\n strcmp\n ksmbd_vfs_compare_durable_owner\n smb2_check_durable_oplock\n smb2_open\n Freed by task kworker:\n kfree\n ksmbd_reopen_durable_fd\n smb2_open\n Allocated by task kworker:\n kstrdup\n session_fd_check\n smb2_session_logoff\n The buggy address belongs to the cache kmalloc-8\n\nSerialize both sides of the race with fp->f_lock. The global durable\nfile-table lock still protects the durable reconnect claim, but\nfp->owner.name is per-open state and does not need to block unrelated\ndurable table lookups or reconnects. The teardown is left at its\nexisting location after the reopen-success point so that an __open_id()\nrollback still retains owner.name for a later legitimate reconnect to\nverify."}], "id": "CVE-2026-72381", "lastModified": "2026-08-17T06:18:42.503", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-15T06:22:11.587", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5a5ac2852cd326529d02f778bc1aa6184701f4d7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/93d4d46bf9d442a12ea87278049ec416962c627f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ed98719be41389d416953b8ef9f07a07dfea6b2b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fb978d72052704c6b06c6b0f129fcd60b77169f5"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ksmbd: fix use-after-free of fp->owner.name in durable handle owner check", "id": "2516299", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2516299"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in ksmbd, the in-kernel SMB3 server for Linux. A remote attacker can exploit a race condition by initiating two concurrent SMB2 durable reconnects with the same persistent ID. This can lead to a use-after-free error, where freed memory is accessed, potentially causing system instability or a denial of service."], "name": "CVE-2026-72381", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-72381\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-72381\nhttps://lore.kernel.org/linux-cve-announce/2026081518-CVE-2026-72381-6021@gregkh/T"], "threat_severity": "Moderate"}

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