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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64388
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:22 UTC
Updated2026-07-27 05:16:45 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.001550000 probability, percentile 0.051570000 (date 2026-07-26)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b326614ea2159ea5c835d320f261d05d080cd201 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e git Not specified
CNA Linux Linux affected b326614ea2159ea5c835d320f261d05d080cd201 760ef2c579c2609cf17fb1cd5392f64d42d43d33 git Not specified
CNA Linux Linux affected 4.18 Not specified
CNA Linux Linux unaffected 4.18 semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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