CVE-2026-109411
Samba: access control bypass via vfs_ceph_rgw case-insensitive open
CVSS Score
8.1
EPSS Score
0.0%
EPSS Percentile
0th
An access control bypass flaw was found in Samba's vfs_ceph_rgw module in it's openat() function. An authenticated user can bypass access controls to read or overwrite restricted files on shares configured with the experimental vfs_ceph_rgw module. When a client requests an existing file using mismatched character casing, the module fails to perform a case-insensitive lookup correctly, causing the server to treat the operation as creating a new file. As a result, the server skips standard permission checks on the existing file, allowing the attacker to access or overwrite sensitive data owned by other users.
| CWE | CWE-178 |
| Vendor | samba |
| Product | samba |
| Published | Oct 28, 2026 |
Stay Ahead of the Next One
Get instant alerts for samba samba
Be the first to know when new high vulnerabilities affecting samba samba are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Samba / Samba
4.25.0 < 4.25.1
Red Hat / Red Hat Enterprise Linux 10
All versions affected Red Hat / Red Hat Enterprise Linux 6
All versions affected Red Hat / Red Hat Enterprise Linux 6
All versions affected Red Hat / Red Hat Enterprise Linux 7
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected Red Hat / Red Hat OpenShift Container Platform 4
All versions affected Red Hat / Red Hat OpenShift Container Platform 4
All versions affected References
access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-109411 attachments.samba.org: https://attachments.samba.org/attachment.cgi?id=19294 attachments.samba.org: https://attachments.samba.org/attachment.cgi?id=19295 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2552136 bugzilla.samba.org: https://bugzilla.samba.org/show_bug.cgi?id=16276
Credits
Red Hat would like to thank hataehoon for reporting this issue.