CVE-2026-64388 | In the Linux kernel, the following vulnerability has been re… | CVSS 7.8 HIGH

Description

In the Linux kernel, the following vulnerability has been resolved: smb/client: fix chown/chgrp with SMB3 POSIX Extensions Ownership (chown) and group (chgrp) modifications were being ignored when mounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or CIFS_MOUNT_MODE_FROM_SID were also explicitly set. Fix this by checking for posix_extensions in cifs_setattr_nounix() when updating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map and set the ownership/group information on the server.

Metadata

CVE ID: CVE-2026-64388
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

7.8 HIGH CVSS 3.1

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

Affected products (2)

Vendor	Product	Platform	Versions
Linux	Linux	—	b326614ea2159ea5c835d320f261d05d080cd201 < 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e, b326614ea2159ea5c835d320f261d05d080cd201 < 760ef2c579c2609cf17fb1cd5392f64d42d43d33
Linux	Linux	—	4.18, 0 < 4.18, 7.1.4 ≤ 7.1., 7.2-rc1 ≤

CVSS scores (1)

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

References (2)