{ "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": "2026-08-17T04:54:31.740Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:54:31.740Z" }, "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", "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" } ] } ] } ], "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" } } } }