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.

CVSS 3.1

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

EPSS

0.1% chance of exploitation in the next 30 days; higher than 2% of CVEs (scores of 2026-10-25)

CWE

CWE-682

Published

2026-07-25

Modified

2026-10-21

Record from

the NVD, synced 2026-10-22

Affected

• linux:linux_kernel

References

• https://git.kernel.org/stable/c/27ead8c5418af6bfab711079fecb9414d78d4cae
• https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec
• https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e
• https://git.kernel.org/stable/c/6825a45f6b8ef76b0ee32649ec3d6e39ca143a18
• https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33

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