Open WebUI: Authenticated users can bypass model access control via exposed query parameter [AI-ASSISTED]

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-45365: 0.19% estimated exploitation activity in the next 30 days; percentile 9.06 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary An internal-only bypassfilter parameter is exposed on the /openai/chat/completions and /ollama/api/chat HTTP endpoints via FastAPI query string binding, allowing any authenticated user to append ?bypassfilter=true and bypass model access control checks to invoke admin-restricted models. Details The generatechatcompletion route handlers in both routers/openai.py and routers/ollama.py declare bypassfilter as a function parameter: routers/openai.py, line 937–941: routers/ollama.py, line 1283–1288: Because FastAPI automatically binds unrecognized function parameters to the query string, any HTTP client can set this value by appending ?bypassfilter=true to the request URL. When bypassfilter is true, the access control check is skipped entirely: routers/openai.py, line 980: This parameter is intended for internal use only — the server-side chat pipeline in utils/chat.py (lines 238, 253) passes bypassfilter=True as a Python function argument when making recursive calls to base…

Published by the source

14 May 2026, 20:25 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:41 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-v6qf-75pr-p96m

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-v6qf-75pr-p96m

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# Patch Next advisory brief: CVE-2026-45365

Advisory: Open WebUI: Authenticated users can bypass model access control via exposed query parameter [AI-ASSISTED]
IDs: CVE-2026-45365, GHSA-v6qf-75pr-p96m
Record: https://patchnext.com/advisories/cve-2026-45365 (revision 2, source checked 26 Oct 2026, 13:41 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: open-webui 0.8.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI open-webui: affected <= 0.8.10; fixed in 0.8.11

## Suggested inspection (read-only)
- `python -m pip show open-webui`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on open-webui.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-v6qf-75pr-p96m (OSV record GHSA-v6qf-75pr-p96m lists affected ranges: PyPI open-webui >=0 <0.8.11 (fixed))
- Verified: https://github.com/advisories/GHSA-v6qf-75pr-p96m (GitHub-reviewed advisory GHSA-v6qf-75pr-p96m lists affected ranges: PyPI open-webui >=0 <=0.8.10)

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