CVE-2026-64388
smb/client: fix chown/chgrp with SMB3 POSIX Extensions
CVSS Score
7.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| Vendor | linux |
| Product | linux |
| Ecosystems | |
| Industries | Technology |
| Published | Jul 25, 2026 |
| Last Updated | Aug 5, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
Linux / Linux
b326614ea2159ea5c835d320f261d05d080cd201 < 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e b326614ea2159ea5c835d320f261d05d080cd201 < 760ef2c579c2609cf17fb1cd5392f64d42d43d33
Linux / Linux
4.18