CVE-2026-43376

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-43376", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.006Z", "datePublished": "2026-05-08T14:21:25.854Z", "dateUpdated": "2026-08-05T12:27:35.730Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:27:35.730Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free by using call_rcu() for oplock_info\n\nksmbd currently frees oplock_info immediately using kfree(), even\nthough it is accessed under RCU read-side critical sections in places\nlike opinfo_get() and proc_show_files().\n\nSince there is no RCU grace period delay between nullifying the pointer\nand freeing the memory, a reader can still access oplock_info\nstructure after it has been freed. This can leads to a use-after-free\nespecially in opinfo_get() where atomic_inc_not_zero() is called on\nalready freed memory.\n\nFix this by switching to deferred freeing using call_rcu()."}], "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 is the in-kernel SMB server reachable over TCP/445, and the vulnerable oplock_info lifetime is exercised by remote SMB2 create/close/oplock and lease operations.\nAC:L - The attacker can create oplocks/leases and drive concurrent requests over SMB connections, so the race is attacker-controlled rather than dependent on an external victim condition.\nPR:N - The path is post-session/tree-connect, but ksmbd supports guest/public shares; in the highest reasonable oplocks-enabled guest-share deployment, no prior credentials are needed.\nUI:N - No victim user action is required once the SMB service and share are available; the attacker sends network protocol requests directly.\nS:U - The vulnerable component and impacted resources are the same kernel/host security authority, with no VM, hypervisor, or other scope boundary crossing.\nC:H - This is a kernel heap use-after-free on oplock_info, including stale pointer dereferences after freed memory can be reallocated, which can reasonably enable high-impact kernel information disclosure.\nI:H - The stale atomic_inc_not_zero and later field accesses can corrupt a reallocated kernel object, making arbitrary kernel memory modification or code execution defensible.\nA:H - The UAF can directly trigger kernel memory corruption, oops, panic, or hang, causing high availability impact."}]}], "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", "fs/smb/server/oplock.h"], "versions": [{"version": "296cb5457cc6f4a754c4ae29855f8a253d52bcc6", "lessThan": "302fef75512b2c8329a3f5efab1ae7ba2562387a", "status": "affected", "versionType": "git"}, {"version": "d54ab1520d43e95f9b2e22d7a05fc9614192e5a5", "lessThan": "08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c", "status": "affected", "versionType": "git"}, {"version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7", "lessThan": "1d6abf145615dbfe267ce3b0a271f95e3780e18e", "status": "affected", "versionType": "git"}, {"version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7", "lessThan": "ce8507ee82c888126d8e7565e27c016308d24cde", "status": "affected", "versionType": "git"}, {"version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7", "lessThan": "1dfd062caa165ec9d7ee0823087930f3ab8a6294", "status": "affected", "versionType": "git"}, {"version": "d73686367ad68534257cd88a36ca3c52cb8b81d8", "status": "affected", "versionType": "git"}, {"version": "6.6.88", "lessThan": "6.6.130", "status": "affected", "versionType": "semver"}, {"version": "6.12.25", "lessThan": "6.12.78", "status": "affected", "versionType": "semver"}, {"version": "6.14.4", "lessThan": "6.15", "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", "fs/smb/server/oplock.h"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "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": "6.6.88", "versionEndExcluding": "6.6.130"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.25", "versionEndExcluding": "6.12.78"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.19"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.19.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.0"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14.4"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a"}, {"url": "https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c"}, {"url": "https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e"}, {"url": "https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde"}, {"url": "https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294"}], "title": "ksmbd: fix use-after-free by using call_rcu() for oplock_info", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/server/oplock.c", "fs/smb/server/oplock.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "302fef75512b2c8329a3f5efab1ae7ba2562387a", "status": "affected", "version": "296cb5457cc6f4a754c4ae29855f8a253d52bcc6", "versionType": "git"}, {"lessThan": "08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c", "status": "affected", "version": "d54ab1520d43e95f9b2e22d7a05fc9614192e5a5", "versionType": "git"}, {"lessThan": "1d6abf145615dbfe267ce3b0a271f95e3780e18e", "status": "affected", "version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7", "versionType": "git"}, {"lessThan": "ce8507ee82c888126d8e7565e27c016308d24cde", "status": "affected", "version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7", "versionType": "git"}, {"lessThan": "1dfd062caa165ec9d7ee0823087930f3ab8a6294", "status": "affected", "version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7", "versionType": "git"}, {"status": "affected", "version": "d73686367ad68534257cd88a36ca3c52cb8b81d8", "versionType": "git"}, {"lessThan": "6.6.130", "status": "affected", "version": "6.6.88", "versionType": "semver"}, {"lessThan": "6.12.78", "status": "affected", "version": "6.12.25", "versionType": "semver"}, {"lessThan": "6.15", "status": "affected", "version": "6.14.4", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/server/oplock.c", "fs/smb/server/oplock.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"lessThan": "6.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.130", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.78", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.19", "versionType": "semver"}, {"lessThanOrEqual": "6.19.*", "status": "unaffected", "version": "6.19.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.0", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "784F219C-5AC7-4D62-AAA6-D30BEF8B27D0", "versionEndExcluding": "6.6.130", "versionStartIncluding": "6.6.88", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "14D96C06-81A5-4885-A783-0D73032A376C", "versionEndExcluding": "6.12.78", "versionStartIncluding": "6.12.25", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "786E593C-5048-4AE0-9421-71BE44AB6058", "versionEndExcluding": "6.15", "versionStartIncluding": "6.14.4", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "B5AFB3C9-B84F-4E20-BC69-DBDBF6A1FA0F", "versionEndExcluding": "6.18.19", "versionStartIncluding": "6.15.1", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "E825E7C3-FEAC-4FD3-8A81-78D7387948C9", "versionEndExcluding": "6.19.9", "versionStartIncluding": "6.19", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:-:*:*:*:*:*:*", "matchCriteriaId": "A1ECC65A-EE37-4479-8E99-4BB68A22A31F", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*", "matchCriteriaId": "13FC0DDE-E513-465E-9E81-515702D49B74", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*", "matchCriteriaId": "8C7B5B0E-4EEB-48F5-B4CF-0935A7633845", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:*", "matchCriteriaId": "2D240580-3048-49B2-9E27-F115A9DF8224", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc6:*:*:*:*:*:*", "matchCriteriaId": "90320558-E553-4EF5-8A0B-0F5D20113BD2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc7:*:*:*:*:*:*", "matchCriteriaId": "C300BA32-5854-4B59-A00A-18A402F291D0", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free by using call_rcu() for oplock_info\n\nksmbd currently frees oplock_info immediately using kfree(), even\nthough it is accessed under RCU read-side critical sections in places\nlike opinfo_get() and proc_show_files().\n\nSince there is no RCU grace period delay between nullifying the pointer\nand freeing the memory, a reader can still access oplock_info\nstructure after it has been freed. This can leads to a use-after-free\nespecially in opinfo_get() where atomic_inc_not_zero() is called on\nalready freed memory.\n\nFix this by switching to deferred freeing using call_rcu()."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nksmbd: corregir uso despu\u00e9s de liberaci\u00f3n mediante el uso de call_rcu() para oplock_info\n\nksmbd actualmente libera oplock_info inmediatamente usando kfree(), a pesar de que se accede a ella bajo secciones cr\u00edticas de lectura de RCU en lugares como opinfo_get() y proc_show_files().\n\nDado que no hay un retraso del per\u00edodo de gracia de RCU entre la anulaci\u00f3n del puntero y la liberaci\u00f3n de la memoria, un lector a\u00fan puede acceder a la estructura oplock_info despu\u00e9s de que haya sido liberada. Esto puede llevar a un uso despu\u00e9s de liberaci\u00f3n, especialmente en opinfo_get() donde se llama a atomic_inc_not_zero() en memoria ya liberada.\n\nCorregir esto cambiando a la liberaci\u00f3n diferida usando call_rcu()."}], "id": "CVE-2026-43376", "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": "2026-05-08T15:16:48.760", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde"}], "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 by using call_rcu() for oplock_info", "id": "2468218", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2468218"}, "csaw": false, "cwe": "CWE-763", "details": ["A flaw was found in ksmbd in the Linux kernel. The `oplock_info` structure is immediately freed using `kfree()` without an RCU (Read-Copy-Update) grace period, even though it can still be accessed by readers. This improper memory deallocation can lead to a use-after-free vulnerability, particularly in the `opinfo_get()` function, where operations are performed on already freed memory. A local attacker could potentially exploit this to cause system instability or a denial of service."], "name": "CVE-2026-43376", "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-2026-43376\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-43376\nhttps://lore.kernel.org/linux-cve-announce/2026050831-CVE-2026-43376-e32d@gregkh/T"]}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[296cb5457cc6f4a754c4ae29855f8a253d52bcc6,302fef75512b2c8329a3f5efab1ae7ba2562387a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[d54ab1520d43e95f9b2e22d7a05fc9614192e5a5,08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[18b4fac5ef17f77fed9417d22210ceafd6525fc7,1d6abf145615dbfe267ce3b0a271f95e3780e18e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[18b4fac5ef17f77fed9417d22210ceafd6525fc7,ce8507ee82c888126d8e7565e27c016308d24cde)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[18b4fac5ef17f77fed9417d22210ceafd6525fc7,1dfd062caa165ec9d7ee0823087930f3ab8a6294)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "d73686367ad68534257cd88a36ca3c52cb8b81d8"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.15"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.15)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.130,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.78,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.19,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.19.9,6.20.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.0,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-05-08T16:15:12.711690+00:00", "updated": "2026-05-15T16:30:03.919056+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}