CVE-2026-64388

HighCVSS 7.8/10Last modified Oct 30, 2026

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.

Metrics

CVSS 3.1 7.8/10CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-682

Affected software

VendorProductVersions
LinuxLinux>= b326614ea2159ea5c835d320f261d05d080cd201, < 6825a45f6b8ef76b0ee32649ec3d6e39ca143a18; >= b326614ea2159ea5c835d320f261d05d080cd201, < 27ead8c5418af6bfab711079fecb9414d78d4cae; >= b326614ea2159ea5c835d320f261d05d080cd201, < 3eaec47518e126e6dcd1a48521d740278073f0ec; >= b326614ea2159ea5c835d320f261d05d080cd201, < 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e; >= b326614ea2159ea5c835d320f261d05d080cd201, < 760ef2c579c2609cf17fb1cd5392f64d42d43d33
LinuxLinux4.18

References

Timeline

Published
Jul 25, 2026
Last modified
Oct 30, 2026
NVD status
Modified

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CVE-2026-64388: High severity, CVSS 7.8 | Vulnix