CVE-2026-64391 | In the Linux kernel, the following vulnerability has been re… | CVSS 9.8 CRITICAL

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.

Metadata

CVE ID: CVE-2026-64391
State: PUBLISHED
Assigner: Linux
Reserved: 2026-07-19 15:36 UTC
Published: 2026-07-25 08:50 UTC
Last updated: 2026-07-27 05:00 UTC
Vendor / Product: Linux / Linux
Sources: cve.org · NVD

Severity & Metrics

9.8 CRITICAL CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products (2)

Vendor	Product	Platform	Versions
Linux	Linux	—	f44158485826c076335d6860d35872271a83791d < a8f5d39971bbad9340d49cd41b0e2da9452a649d, f44158485826c076335d6860d35872271a83791d < 2b4592cea214683de0f2ce6f8c22c097fb0ea1ab, f44158485826c076335d6860d35872271a83791d < 52a56cf53ec834c44ac1b4d16d585f26613ee5ce, f44158485826c076335d6860d35872271a83791d < baa5e094886fffa7e6272edcb5e08be5ce28262c
Linux	Linux	—	5.15, 0 < 5.15, 6.12.96 ≤ 6.12., 6.18.39 ≤ 6.18. …

CVSS scores (1)

Score	Severity	Version	Source	Vector
9.8	CRITICAL	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References (4)