{ "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" } } } }