CVE-2026-64388

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxb326614ea2159ea5c835d320f261d05d080cd201 < 550cfb8a81181331d4d0f76ab75ee58a0bf41e3eaffected
LinuxLinuxb326614ea2159ea5c835d320f261d05d080cd201 < 760ef2c579c2609cf17fb1cd5392f64d42d43d33affected
LinuxLinux4.18affected
LinuxLinux0 < 4.18unaffected
LinuxLinux7.1.4 <= 7.1.*unaffected
LinuxLinux7.2-rc1 <= *unaffected

Weaknesses

References