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CVE-2026-64388high

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

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.8epss 0.1%
exploitation probability
0.1%top 98% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
Linux · Linux