CVE-2026-64391

ksmbd: use opener credentials for ADS I/O

State: Published
Severity: 9.8 Critical
Published: Jul 25, 2026
Updated: Oct 30, 2026
Reserved: Jul 19, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	f44158485826c076335d6860d35872271a83791d to before 222c4c52c3af2d0f68de31182710df3508a31095Affected f44158485826c076335d6860d35872271a83791d to before 2ad5509dd576ae16d252d4698daf03002f9e0234Affected f44158485826c076335d6860d35872271a83791d to before a8f5d39971bbad9340d49cd41b0e2da9452a649dAffected f44158485826c076335d6860d35872271a83791d to before 2b4592cea214683de0f2ce6f8c22c097fb0ea1abAffected f44158485826c076335d6860d35872271a83791d to before 52a56cf53ec834c44ac1b4d16d585f26613ee5ceAffected f44158485826c076335d6860d35872271a83791d to before baa5e094886fffa7e6272edcb5e08be5ce28262cAffected
LinuxLinux	5.15Affected before 5.15Not affected 6.1.191 through 6.1.Not affected 6.6.160 through 6.6.Not affected 6.12.96 through 6.12.Not affected 6.18.39 through 6.18.Not affected 7.1.4 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

f44158485826c076335d6860d35872271a83791d to before 222c4c52c3af2d0f68de31182710df3508a31095Affected
f44158485826c076335d6860d35872271a83791d to before 2ad5509dd576ae16d252d4698daf03002f9e0234Affected
f44158485826c076335d6860d35872271a83791d to before a8f5d39971bbad9340d49cd41b0e2da9452a649dAffected
f44158485826c076335d6860d35872271a83791d to before 2b4592cea214683de0f2ce6f8c22c097fb0ea1abAffected
f44158485826c076335d6860d35872271a83791d to before 52a56cf53ec834c44ac1b4d16d585f26613ee5ceAffected
f44158485826c076335d6860d35872271a83791d to before baa5e094886fffa7e6272edcb5e08be5ce28262cAffected

LinuxLinux

5.15Affected
before 5.15Not affected
6.1.191 through 6.1.*Not affected
6.6.160 through 6.6.*Not affected
6.12.96 through 6.12.*Not affected
6.18.39 through 6.18.*Not affected
7.1.4 through 7.1.*Not affected
7.2 and laterNot affected

References

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