CVE-2026-64388

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.

• git.kernel.orghttps://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e
• git.kernel.orghttps://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33

No related CVEs by CWE or product.