CVE-2026-64388
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.
SeverityHigh
CVSS7.8
Exploit probability—
Product
Linux Kernel
PublishedJul 25, 2026
First seenJul 25, 2026
Weakness typeCWE-682CWE-682
How to fix
Update
- linux linux_kernel7.1.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 4.18 ≤ v < 7.1.4 | 7.1.4 |
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