{"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"}}}}