High 7.8Published Jul 25, 2026

CVE-2026-64388smb/client: fix chown/chgrp with SMB3 POSIX Extensions

Updated under an hour ago (2026-10-19 06:20 UTC)

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Exploited in the last 30 days

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: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 16, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from b326614ea2159ea5c835d320f261d05d080cd201 before 3eaec47518e126e6dcd1a48521d740278073f0ec; from b326614ea2159ea5c835d320f261d05d080cd201 before 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e; from b326614ea2159ea5c835d320f261d05d080cd201 before 760ef2c579c2609cf17fb1cd5392f64d42d43d33	CNA record
linux linux_kernel linux:linux_kernel	from 4.18 before 7.1.4	NVD

References

https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec
https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3epatch
https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.