by Kastro
Paper/Archive/CVE-2026-64391

CVE-2026-64391

Linux Linux — ksmbd: use opener credentials for ADS I/O

EPSS 0.5%CVSS 9.8
critical.is priorityof 100
37
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 39.6.396 × 207.9No public exploit+100.0SSVC exploitation: unknown+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Linuxf44158485826c076335d6860d35872271a83791d – < 2ad5509dd576ae16d252d4698daf03002f9e02342ad5509dd576ae16d252d4698daf03002f9e0234CNA
Linuxf44158485826c076335d6860d35872271a83791d – < a8f5d39971bbad9340d49cd41b0e2da9452a649da8f5d39971bbad9340d49cd41b0e2da9452a649dCNA
Linuxf44158485826c076335d6860d35872271a83791d – < 2b4592cea214683de0f2ce6f8c22c097fb0ea1ab2b4592cea214683de0f2ce6f8c22c097fb0ea1abCNA
Linuxf44158485826c076335d6860d35872271a83791d – < 52a56cf53ec834c44ac1b4d16d585f26613ee5ce52a56cf53ec834c44ac1b4d16d585f26613ee5ceCNA
Linuxf44158485826c076335d6860d35872271a83791d – < baa5e094886fffa7e6272edcb5e08be5ce28262cbaa5e094886fffa7e6272edcb5e08be5ce28262cCNA
Linux5.15–CNA

Scores by source

Linux (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

refgit.kernel.org/stable/c/2ad5509dd576ae16d252d4698daf03002f9e0234refgit.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649drefgit.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1abrefgit.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5cerefgit.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c