CVE-2026-64388 PUBLISHED

smb/client: fix chown/chgrp with SMB3 POSIX Extensions

Assigner: Linux
Reserved: 19.07.2026 Published: 25.07.2026 Updated: 25.07.2026

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.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e (excl.)
  • affected from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to 760ef2c579c2609cf17fb1cd5392f64d42d43d33 (excl.)
  • affected from 0 to 7.1.4 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • unaffected from 7.1.4 to 7.1.* (incl.)
  • unaffected from 7.2-rc1 to * (incl.)

References