{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64393", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.785Z", "datePublished": "2026-07-25T08:50:39.239Z", "dateUpdated": "2026-08-17T04:54:46.744Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:54:46.744Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: run set info with opener credentials\n\nSMB2 SET_INFO handlers call path-based VFS helpers after checking the\naccess mask granted to the SMB handle. Those helpers perform their owner,\ninode permission and LSM checks using the current ksmbd worker credentials.\n\nRun the complete SET_INFO dispatch with the credentials captured when the\nhandle was opened. This also removes the separate security information\ncredential setup and keeps all SET_INFO classes under one credential scope.\n\nDirect override_creds() is used because it can nest with the request\ncredential overrides already used by rename and link helpers." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable SMB2 SET_INFO handler is remotely reachable through ksmbd over TCP/445 or SMB Direct.\nAC:L - An attacker can deterministically open a handle and send a crafted SET_INFO request; no race or condition outside the attacker’s control is required.\nPR:N - Although a valid SMB session, writable tree, and suitable handle are required, ksmbd supports passwordless guest sessions on writable shares, making exploitation possible without attacker privileges in a reasonable deployment.\nUI:N - The attacker directly opens the handle and submits the SET_INFO request without any victim action.\nS:U - The bypass affects files and services governed by the same host kernel and filesystem security authority, without crossing a virtualization or sandbox boundary.\nC:N - The flaw provides unauthorized mutation through metadata, xattr, and truncation operations but does not itself disclose file contents or kernel memory.\nI:H - Privileged worker credentials can bypass opener UID, group, capability, inode, and LSM checks, permitting protected metadata changes and destructive truncation of an affected file.\nA:H - Repeated SET_INFO requests can truncate critical files or corrupt security-relevant metadata and xattrs, potentially disabling dependent services or exhausting filesystem resources." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/smb2pdu.c" ], "versions": [ { "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "5cbabf3a71575cd31bc7785d92d4ab42338a654b", "status": "affected", "versionType": "git" }, { "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "b35afd5cf8fab236ef21117e42ee45691d4ffa7b", "status": "affected", "versionType": "git" }, { "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "0ce682867fd506f61f40c76bde7e4205bde34e87", "status": "affected", "versionType": "git" }, { "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "20ee516a62989a8d505ee432f9e59525ea23984e", "status": "affected", "versionType": "git" }, { "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "8cc9ec711f5255167247a9ab6a7179b787426ed7", "status": "affected", "versionType": "git" }, { "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9", "lessThan": "b383bcad3d2fe634b26efbce53e22bbb5753a520", "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/smb2pdu.c" ], "versions": [ { "version": "5.15", "status": "affected" }, { "version": "0", "lessThan": "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": "5.15", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5cbabf3a71575cd31bc7785d92d4ab42338a654b" }, { "url": "https://git.kernel.org/stable/c/b35afd5cf8fab236ef21117e42ee45691d4ffa7b" }, { "url": "https://git.kernel.org/stable/c/0ce682867fd506f61f40c76bde7e4205bde34e87" }, { "url": "https://git.kernel.org/stable/c/20ee516a62989a8d505ee432f9e59525ea23984e" }, { "url": "https://git.kernel.org/stable/c/8cc9ec711f5255167247a9ab6a7179b787426ed7" }, { "url": "https://git.kernel.org/stable/c/b383bcad3d2fe634b26efbce53e22bbb5753a520" } ], "title": "ksmbd: run set info with opener credentials", "x_generator": { "engine": "bippy-1.2.0" } } } }