{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64391", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.785Z", "datePublished": "2026-07-25T08:50:38.013Z", "dateUpdated": "2026-10-30T12:27:51.381Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:27:51.381Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use opener credentials for ADS I/O\n\nAlternate data streams are stored as xattrs. Unlike regular file I/O,\ntheir read and write paths therefore call VFS xattr helpers which recheck\ninode permissions and LSM policy using the current task credentials.\n\nRun ADS I/O with the credentials captured when the SMB handle was opened." } ], "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 - An attacker reaches the vulnerable ADS read and write paths through SMB2 requests to an exposed ksmbd server over TCP/445.\nAC:L - Exploitation is deterministic using an ADS handle followed by ordinary SMB2 READ or WRITE requests; no race, memory-layout dependency, or condition outside the attacker's control is required.\nPR:N - Although a valid session, tree connection, and handle are required, a guest-enabled streams share permits a remote client to establish the necessary guest session without supplying valid credentials.\nUI:N - The attacker directly opens and accesses the alternate data stream through SMB requests without requiring any victim action.\nS:U - The credential bypass affects ADS data managed by the same host kernel and filesystem security authority; it does not cross a virtualization or comparable isolation boundary.\nC:H - Privileged worker credentials can bypass inode and LSM xattr checks and disclose the complete contents of an attacker-selected named stream, including potentially sensitive application data.\nI:H - The vulnerable write path can bypass xattr authorization and replace or truncate the complete named stream with attacker-controlled data.\nA:H - Repeated unauthorized truncation or corruption can persistently destroy an ADS and render applications or services that depend on that stream unusable until the data is restored." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/vfs.c" ], "versions": [ { "version": "f44158485826c076335d6860d35872271a83791d", "lessThan": "222c4c52c3af2d0f68de31182710df3508a31095", "status": "affected", "versionType": "git" }, { "version": "f44158485826c076335d6860d35872271a83791d", "lessThan": "2ad5509dd576ae16d252d4698daf03002f9e0234", "status": "affected", "versionType": "git" }, { "version": "f44158485826c076335d6860d35872271a83791d", "lessThan": "a8f5d39971bbad9340d49cd41b0e2da9452a649d", "status": "affected", "versionType": "git" }, { "version": "f44158485826c076335d6860d35872271a83791d", "lessThan": "2b4592cea214683de0f2ce6f8c22c097fb0ea1ab", "status": "affected", "versionType": "git" }, { "version": "f44158485826c076335d6860d35872271a83791d", "lessThan": "52a56cf53ec834c44ac1b4d16d585f26613ee5ce", "status": "affected", "versionType": "git" }, { "version": "f44158485826c076335d6860d35872271a83791d", "lessThan": "baa5e094886fffa7e6272edcb5e08be5ce28262c", "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/vfs.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": "6.12.96", "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": "6.1.191" }, { "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": "6.12.96" }, { "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/222c4c52c3af2d0f68de31182710df3508a31095" }, { "url": "https://git.kernel.org/stable/c/2ad5509dd576ae16d252d4698daf03002f9e0234" }, { "url": "https://git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d" }, { "url": "https://git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab" }, { "url": "https://git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce" }, { "url": "https://git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c" } ], "title": "ksmbd: use opener credentials for ADS I/O", "x_generator": { "engine": "bippy-1.2.0" } } } }