CVE-2026-64138

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they control both the crafted on-disk descriptor and the concurrent SMB request that exercises inheritance.\nPR:L - Exploitation requires an authenticated SMB2 session with write permission on the parent directory to create files; this is not a pre-authentication code path but does not require host root or special kernel capabilities.\nUI:N - Exploitation is fully automated over the SMB protocol and does not require any action from a separate victim user beyond normal server operation.\nS:U - The vulnerability is confined to the kernel's ksmbd security context and does not cross a VM, container, or IOMMU security boundary.\nC:H - The unchecked SID size computation and memcpy perform an out-of-bounds kernel heap read; stolen memory can be embedded in the newly created file's security descriptor and retrieved by the attacker.\nI:H - Unvalidated out-of-bounds memory access is a memory corruption primitive in kernel context; per kernel CVSS guidance, such bugs are scored at High integrity impact even when the immediate fault is a read.\nA:H - Reading from attacker-controlled out-of-bounds offsets can dereference unmapped or invalid kernel memory, causing an oops or panic and denying SMB service."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/smbacl.c"], "versions": [{"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "f7c4dee323d9176b8d3f5c69018ee57ae0d4653c", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "8efbea0253b7fa2d1960cab0fed36544ca0b41ab", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "f0e5c9c663badc9982e6941322eef1cb17de0f11", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "18d8db24b0a5b7be4829238dd4022236df02d421", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "1c9d0646a9959752f11ca1080dc1ff26bd1756cb", "status": "affected", "versionType": "git"}, {"version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "69f030cf95488ae1186c72ac8c66fd279664ea7f", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/smbacl.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.34", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.11", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "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": "5.15", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.92"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.0.11"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/f7c4dee323d9176b8d3f5c69018ee57ae0d4653c"}, {"url": "https://git.kernel.org/stable/c/8efbea0253b7fa2d1960cab0fed36544ca0b41ab"}, {"url": "https://git.kernel.org/stable/c/f0e5c9c663badc9982e6941322eef1cb17de0f11"}, {"url": "https://git.kernel.org/stable/c/18d8db24b0a5b7be4829238dd4022236df02d421"}, {"url": "https://git.kernel.org/stable/c/1c9d0646a9959752f11ca1080dc1ff26bd1756cb"}, {"url": "https://git.kernel.org/stable/c/69f030cf95488ae1186c72ac8c66fd279664ea7f"}], "title": "ksmbd: validate SID in parent security descriptor during ACL inheritance", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

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"versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "3FE535DF-ECA8-4702-A755-AE672E94D5B1", "versionEndExcluding": "6.12.92", "versionStartIncluding": "5.15", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "A4B1EF6D-18D7-4838-BC37-7499D5DCC3C0", "versionEndExcluding": "6.18.34", "versionStartIncluding": "6.13", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "0520D091-FC52-4A50-AF07-70AE7D08B750", "versionEndExcluding": "7.0.11", "versionStartIncluding": "6.19", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*", "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390", "vulnerable": 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"attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-19T16:17:55.680", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/18d8db24b0a5b7be4829238dd4022236df02d421"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/1c9d0646a9959752f11ca1080dc1ff26bd1756cb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/69f030cf95488ae1186c72ac8c66fd279664ea7f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8efbea0253b7fa2d1960cab0fed36544ca0b41ab"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f0e5c9c663badc9982e6941322eef1cb17de0f11"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f7c4dee323d9176b8d3f5c69018ee57ae0d4653c"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: ksmbd: validate SID in parent security descriptor during ACL inheritance", "id": "2502495", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502495"}, "csaw": false, "cwe": "CWE-639", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nksmbd: validate SID in parent security descriptor during ACL inheritance\nIntroduce smb_validate_ntsd_sid() helper to safely validate Owner SID\nand Group SID inside the NT Security Descriptor (smb_ntsd) retrieved\nfrom the parent directory.", "A flaw was found in the ksmbd module of the Linux kernel. This vulnerability arises from improper validation of Security Identifiers (SIDs) within the NT Security Descriptor (smb_ntsd) during Access Control List (ACL) inheritance. An attacker could exploit this to bypass intended security restrictions, potentially leading to unauthorized access to resources."], "name": "CVE-2026-64138", "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"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Not affected", "impact": "moderate", "package_name": "erlang27", "product_name": "Red Hat Hardened Images"}], "public_date": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64138\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64138\nhttps://lore.kernel.org/linux-cve-announce/2026071928-CVE-2026-64138-e6dd@gregkh/T"]}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9,f0e5c9c663badc9982e6941322eef1cb17de0f11)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9,18d8db24b0a5b7be4829238dd4022236df02d421)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9,1c9d0646a9959752f11ca1080dc1ff26bd1756cb)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9,69f030cf95488ae1186c72ac8c66fd279664ea7f)"}}], "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": "generic", "value": "5.15"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,5.15)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.92,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.34,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.11,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "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": "2026-07-21T11:00:05.269831+00:00", "updated": "2026-08-18T15:15:03.815625+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}