# CVE-2026-109411: Samba: access control bypass via vfs_ceph_rgw case-insensitive open


- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-109411, GHSA-pwp9-3h93-h2x8, UBUNTU-CVE-2026-109411, openSUSE-SU-2026:12334-1

## What is CVE-2026-109411?

CVE-2026-109411 is a high-severity vulnerability in Red Hat Enterprise Linux 10, published on 28 Oct 2026. 

### Official 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.

Weakness: CWE-178 (Improper Handling of Case Sensitivity)

## Which versions are affected by CVE-2026-109411?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `samba` | openSUSE:Tumbleweed | All versions | 4.25.1+git.476.bfc358351cb-1.1 |

## How do I fix CVE-2026-109411?

Upgrade to a fixed version.

## Is CVE-2026-109411 being exploited?

There is no known exploitation of CVE-2026-109411 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-109411 and fix it if it is affected.

What it is: CVE-2026-109411 is a high-severity vulnerability in Red Hat Enterprise Linux 10, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-109411 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-109411/ (Markdown: https://insights.sbomify.com/CVE-2026-109411/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-109411
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-109411
- OSV: https://osv.dev/vulnerability/CVE-2026-109411

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-109411/
Summaries are generated and may contain mistakes; the official description above is the record.