# CVE-2026-44556: Open WebUI: responses passthrough endpoint lacks access control authorization

> Authenticated users can bypass model access controls to interact with any configured LLM via the responses endpoint.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 May 2026
- **Updated:** 15 May 2026
- **Also known as:** GHSA-hp5m-24vp-vq2q, PYSEC-2026-2734

## What is CVE-2026-44556?

CVE-2026-44556 is a high-severity missing authorization vulnerability in Openwebui Open Webui, published on 15 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the /responses endpoint in the OpenAI router accepts any authenticated user and forwards requests directly to upstream LLM providers without enforcing per-model access control. While the primary chat completion endpoint (generate_chat_completion) checks model ownership, group membership, and AccessGrants before allowing a request, the /responses proxy only validates that the user has a valid session via get_verified_user. This allows any authenticated user to interact with any model configured on the instance by sending a POST request to /api/openai/responses with an arbitrary model ID. This vulnerability is fixed in 0.9.0.

Weakness: CWE-862 (Missing Authorization), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-44556?

3 open source packages ship an affected version, including open-webui. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `open-webui` | PyPI | All versions | 0.9.0 |
| `open-webui` | PyPI | All versions | 0.9.0 |
| `open-webui` | PyPI | All versions | 0.9.0 |

Products: Openwebui Open Webui.

## How do I fix CVE-2026-44556?

Upgrade open-webui to 0.9.0 or later.

## Is CVE-2026-44556 being exploited?

There is no known exploitation of CVE-2026-44556 in the wild and no public exploit code.

## Other vulnerabilities in Openwebui Open Webui

- [CVE-2026-44551](https://insights.sbomify.com/CVE-2026-44551/): Open WebUI: LDAP Empty Password Authentication Bypass (critical 9.1)
- [CVE-2026-56400](https://insights.sbomify.com/CVE-2026-56400/): open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation (critical 9.0)
- [CVE-2024-8017](https://insights.sbomify.com/CVE-2024-8017/): Cross-site Scripting (XSS) in open-webui/open-webui (critical 9.0)
- [CVE-2026-45672](https://insights.sbomify.com/CVE-2026-45672/): Open WebUI: Jupyter code execution works despite `ENABLE_CODE_EXECUTION=false` — feature gate bypassed (high 8.8)
- [CVE-2026-87995](https://insights.sbomify.com/CVE-2026-87995/): Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44556 and fix it if it is affected.

What it is: CVE-2026-44556 is a high-severity missing authorization vulnerability in Openwebui Open Webui, published on 15 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-44556 in the wild and no public exploit code.

Affected packages and fixed versions:
- open-webui (PyPI): affected all versions; fixed in 0.9.0
- open-webui (PyPI): affected all versions; fixed in 0.9.0
- open-webui (PyPI): affected all versions; fixed in 0.9.0

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-2026-44556/ (Markdown: https://insights.sbomify.com/CVE-2026-44556/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44556
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44556
- OSV: https://osv.dev/vulnerability/CVE-2026-44556

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44556/
Summaries are generated and may contain mistakes; the official description above is the record.