ksmbd: use opener credentials for ADS I/O
In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for ADS I/O Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials. Run ADS I/O with the credentials captured when the SMB handle was opened.
02 / AFFECTED SOFTWARE
Affected packages
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for ADS I/O Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials. Run ADS I/O with the credentials captured when the SMB handle was opened.
05 / REFERENCES
Further evidence
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab
- https://git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce
- https://git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d
- https://git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64391.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-64391