CVE-2026-43379

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-43379", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.006Z", "datePublished": "2026-05-08T14:21:28.027Z", "dateUpdated": "2026-08-05T12:27:39.686Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:27:39.686Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in smb_lazy_parent_lease_break_close()\n\nopinfo pointer obtained via rcu_dereference(fp->f_opinfo) is being\naccessed after rcu_read_unlock() has been called. This creates a\nrace condition where the memory could be freed by a concurrent\nwriter between the unlock and the subsequent pointer dereferences\n(opinfo->is_lease, etc.), leading to a use-after-free."}], "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 - ksmbd processes SMB2 traffic over the network on TCP/445, and the vulnerable close path is reached through SMB2 create/write/close requests from a remote client.\nAC:L - The attacker can create v2 lease state, trigger `reserve_lease_break` with SMB2 write, and repeatedly drive concurrent close/opinfo teardown using their own SMB requests or connections. The race is attacker-influenced and repeatable, so no external uncontrollable condition is required.\nPR:N - The path is post-session/tree-connect, but ksmbd supports guest/anonymous sessions and guest-access shares; in that reasonable deployment no prior credentials are needed. Under the required higher-severity rule, this is scored as no privileges required.\nUI:N - No victim user action is required after the ksmbd service and share are available; the attacker sends SMB requests directly.\nS:U - The vulnerable component and impacted resources are the same kernel/ksmbd security authority. This is not a VM escape, IOMMU bypass, or cross-scope boundary violation.\nC:H - This is a use-after-free of `oplock_info`/lease state after dropping the RCU read lock. Freed kernel objects may be reclaimed and shaped through repeated SMB activity, making high confidentiality impact defensible.\nI:H - Use-after-free in kernel heap objects can be leveraged beyond a crash through object reuse and control-flow or data-structure corruption. Following the required UAF guidance, integrity impact is high.\nA:H - Even without full exploitation, dereferencing freed `oplock_info` or `o_lease` memory can cause a kernel oops or panic. The vulnerable path is remotely triggerable and repeatable, so availability impact is high."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/oplock.c"], "versions": [{"version": "27b40b7bfcd121fe13a150ffe11957630cf49246", "lessThan": "bf4d66d72e4a9e268c1012c331ce9eaedb5e2086", "status": "affected", "versionType": "git"}, {"version": "5fb282ba4fef8985a5acf2b32681f2ec07732561", "lessThan": "960699317d39f46611f4ebeb69edc567c1f4e6b6", "status": "affected", "versionType": "git"}, {"version": "5fb282ba4fef8985a5acf2b32681f2ec07732561", "lessThan": "dbbd328cf58261ca239756fe1c0d10c9518d3399", "status": "affected", "versionType": "git"}, {"version": "5fb282ba4fef8985a5acf2b32681f2ec07732561", "lessThan": "b3568347c51c46e2cabc356bc34676df98296619", "status": "affected", "versionType": "git"}, {"version": "5fb282ba4fef8985a5acf2b32681f2ec07732561", "lessThan": "eac3361e3d5dd8067b3258c69615888eb45e9f25", "status": "affected", "versionType": "git"}, {"version": "6.6.32", "lessThan": "6.6.130", "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/oplock.c"], "versions": [{"version": "6.9", "status": "affected"}, {"version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.130", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.78", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.19", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19.9", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0", "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": "6.6.32", "versionEndExcluding": "6.6.130"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.12.78"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.19"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.19.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.0"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/bf4d66d72e4a9e268c1012c331ce9eaedb5e2086"}, {"url": "https://git.kernel.org/stable/c/960699317d39f46611f4ebeb69edc567c1f4e6b6"}, {"url": "https://git.kernel.org/stable/c/dbbd328cf58261ca239756fe1c0d10c9518d3399"}, {"url": "https://git.kernel.org/stable/c/b3568347c51c46e2cabc356bc34676df98296619"}, {"url": "https://git.kernel.org/stable/c/eac3361e3d5dd8067b3258c69615888eb45e9f25"}], "title": "ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

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This creates a\nrace condition where the memory could be freed by a concurrent\nwriter between the unlock and the subsequent pointer dereferences\n(opinfo->is_lease, etc.), leading to a use-after-free."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:\n\nksmbd: correcci\u00f3n de uso despu\u00e9s de liberaci\u00f3n en smb_lazy_parent_lease_break_close()\n\nEl puntero opinfo obtenido a trav\u00e9s de rcu_dereference(fp -> f_opinfo) est\u00e1 siendo accedido despu\u00e9s de que se haya llamado a rcu_read_unlock(). Esto crea una condici\u00f3n de carrera donde la memoria podr\u00eda ser liberada por un escritor concurrente entre la liberaci\u00f3n del bloqueo y las subsiguientes desreferencias del puntero (opinfo -> is_lease, etc.), lo que lleva a un uso despu\u00e9s de liberaci\u00f3n."}], "id": "CVE-2026-43379", "lastModified": "2026-11-11T20:10:00.273", "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": "2026-05-08T15:16:49.100", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/960699317d39f46611f4ebeb69edc567c1f4e6b6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b3568347c51c46e2cabc356bc34676df98296619"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/bf4d66d72e4a9e268c1012c331ce9eaedb5e2086"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/dbbd328cf58261ca239756fe1c0d10c9518d3399"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/eac3361e3d5dd8067b3258c69615888eb45e9f25"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close()", "id": "2468199", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2468199"}, "csaw": false, "cwe": "CWE-825", "details": ["A flaw was found in ksmbd, a component of the Linux kernel. A race condition exists where a pointer to `opinfo` is accessed after its associated memory may have been freed by a concurrent operation. This use-after-free vulnerability can lead to memory corruption, potentially causing system instability or a denial of service (DoS)."], "name": "CVE-2026-43379", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not 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": "2026-05-08T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-43379\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-43379\nhttps://lore.kernel.org/linux-cve-announce/2026050832-CVE-2026-43379-1808@gregkh/T"]}

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