{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64380", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.784Z", "datePublished": "2026-07-25T08:50:30.476Z", "dateUpdated": "2026-08-05T12:41:16.202Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:41:16.202Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers with only one\nremaining byte. Require two bytes before reading sid[1] so all client\npaths that reuse the helper reject truncated POSIX SIDs safely."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H", "baseScore": 8.2, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - A malicious SMB server can deliver the truncated POSIX SID through SMB3.1.1 query-info or query-directory responses over TCP.\nAC:L - The server directly controls the response length and can deterministically leave exactly one SID byte remaining; no race or uncontrollable condition is required.\nPR:N - The malicious server needs no privileges on the vulnerable client, and guest-capable or attacker-controlled shares can supply the response after connection establishment.\nUI:N - On an already mounted POSIX-enabled share, routine automated stat, readdir, or metadata operations can trigger parsing without human interaction.\nS:U - The out-of-bounds access occurs within the client kernel and does not cross a virtualization, IOMMU, or other separate security authority boundary.\nC:L - The primitive reads exactly one byte beyond the response boundary, limiting any confidentiality effect to adjacent memory rather than providing an arbitrary-read primitive.\nI:N - The out-of-bounds byte only influences validation, which always rejects because a legal SID requires at least 12 bytes; no attacker-influenced copy or memory write follows.\nA:H - The server can place the truncated SID at the receive allocation boundary, where the out-of-bounds access can trigger a sanitizer fault or kernel oops and can be repeated to crash the client."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/smb2pdu.c"], "versions": [{"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "171605aed68380c2fa75dff9b3a1ed427c50065b", "status": "affected", "versionType": "git"}, {"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "4213c1208978483021d7d125c131de3985d38f61", "status": "affected", "versionType": "git"}, {"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "96e889bc1e759c83f25093e8c2f3da31b4973f30", "status": "affected", "versionType": "git"}, {"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "0de5b8e76847f5de26f364a82c6602c4881c30da", "status": "affected", "versionType": "git"}, {"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "427eb7eb46425fec845a43e861f3d6e2899cae59", "status": "affected", "versionType": "git"}, {"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "86c5d470f5d42e61123b2f4b4f0b91f4eee5b980", "status": "affected", "versionType": "git"}, {"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "46a84715a015cb48e1b9c219dc88c03d8a541ea4", "status": "affected", "versionType": "git"}, {"version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "lessThan": "7ad2bcf2441430bb2e918fb3ef9a90d775a6e422", "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/client/smb2pdu.c"], "versions": [{"version": "5.7", "status": "affected"}, {"version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2-rc2", "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": "5.7", "versionEndExcluding": "5.10.261"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.212"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.178"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.96"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.39"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.1.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.2-rc2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b"}, {"url": "https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61"}, {"url": "https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30"}, {"url": "https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da"}, {"url": "https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59"}, {"url": "https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980"}, {"url": "https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4"}, {"url": "https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422"}], "title": "smb: client: harden POSIX SID length parsing", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/client/smb2pdu.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "171605aed68380c2fa75dff9b3a1ed427c50065b", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}, {"lessThan": "4213c1208978483021d7d125c131de3985d38f61", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}, {"lessThan": "96e889bc1e759c83f25093e8c2f3da31b4973f30", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}, {"lessThan": "0de5b8e76847f5de26f364a82c6602c4881c30da", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}, {"lessThan": "427eb7eb46425fec845a43e861f3d6e2899cae59", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}, {"lessThan": "86c5d470f5d42e61123b2f4b4f0b91f4eee5b980", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}, {"lessThan": "46a84715a015cb48e1b9c219dc88c03d8a541ea4", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}, {"lessThan": "7ad2bcf2441430bb2e918fb3ef9a90d775a6e422", "status": "affected", "version": "349e13ad30b45998bb9937cfe0b32be6f951976d", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/client/smb2pdu.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.7"}, {"lessThan": "5.7", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.261", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.212", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.178", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.145", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.96", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.39", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2-rc2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers with only one\nremaining byte. Require two bytes before reading sid[1] so all client\npaths that reuse the helper reject truncated POSIX SIDs safely."}], "id": "CVE-2026-64380", "lastModified": "2026-08-11T15:01:50.637", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.2, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 4.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-25T10:17:21.220", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

{"bugzilla": {"description": "kernel: smb: client: harden POSIX SID length parsing", "id": "2507145", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507145"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["A flaw was found in the Linux kernel's Server Message Block (SMB) client. The vulnerability exists in the `posix_info_sid_size()` function, which is responsible for parsing POSIX Security Identifiers (SIDs). An insufficient boundary check allows the system to accept truncated POSIX SIDs, which could lead to unexpected behavior or a denial of service. This issue has been resolved by requiring at least two bytes before reading the subauthority count, ensuring that all client paths safely reject malformed SIDs."], "name": "CVE-2026-64380", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "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": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-25T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64380\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64380\nhttps://lore.kernel.org/linux-cve-announce/2026072525-CVE-2026-64380-95d8@gregkh/T"], "threat_severity": "Moderate"}

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