# CVE-2026-109411: samba: An access control bypass flaw was identified in Samba's vfs_ceph_rgw module in it's openat() function

CVE-2026-109411 is fixed in samba on 1 platform by DEBIAN-CVE-2026-109411 (version 2:4.25.1+dfsg-1), released October 27, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-109411
- Priority: High
- CVSS: 8.1 (high)
- EPSS: 0.0065
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 28, 2026

## Description

An access control bypass flaw was identified 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | samba Debian 14 | 2:4.25.1+dfsg-1 | [DEBIAN-CVE-2026-109411](https://patchblox.com/security/data/fix/linux/debian-cve-2026-109411.md) | Oct 27, 2026 |

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Data as of 2026-11-10T07:50:38Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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