{"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":"2026-08-17T04:54:43.832Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T04:54:43.832Z"},"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":"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":"6.12.96","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":"6.12.96"},{"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/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"}}}}