CVE-2026-45339: API Key Restriction Bypass in Open WebUI

# CVE-2026-45339: API Key Restriction Bypass in Open WebUI

https://gcdradar.vercel.app/incidents/cve-2026-45339-api-key-restriction-bypass-in-open-webui · AIR-2026-1079 · closed 2026-05-15

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Patched
- First reported: 2026-05-14 (happened 2026-05-15)
- AI role: Attack on AI
- Products: Open WebUI
- CVE ids: CVE-2026-45339
- CVSS: 6.5

## Summary

An authentication header bypass in Open WebUI allows restricted API keys to access blocked message endpoints. The issue has been patched in version 0.9.0.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Affected and fixed versions

- Affected: open-webui < 0.9.0
- Fixed in: open-webui 0.9.0

## Latest updates

- 2026-05-15: CVE-2026-45339: Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. (https://nvd.nist.gov/vuln/detail/CVE-2026-45339)
- 2026-05-14: GitHub advisory published (https://github.com/advisories/GHSA-57q6-fvp4-pqmm)

## Sources

- 2026-05-14 GitHub Advisory Database: CVE-2026-45339: Open WebUI's API key endpoint restrictions bypassed via `x-api-key` header — full message processing on restricted endpoints https://github.com/advisories/GHSA-57q6-fvp4-pqmm
- 2026-05-15 NVD: CVE-2026-45339: Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. https://nvd.nist.gov/vuln/detail/CVE-2026-45339

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.