CVE-2026-59223: Open WebUI WEB_FETCH_FILTER_LIST host filter bypass

# CVE-2026-59223: Open WebUI WEB_FETCH_FILTER_LIST host filter bypass

https://gcdradar.vercel.app/incidents/cve-2026-59223-open-webui-web-fetch-filter-list-host-filter · AIR-2026-0858 · closed 2026-07-09

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-07-09 (happened 2026-07-24)
- AI role: Attack on AI
- Products: Open WebUI
- CVE ids: CVE-2026-59223
- CVSS: 4.3

## Summary

Improper hostname validation and string matching in Open WebUI allows administrators' allow or block fetch lists to be bypassed via URL path manipulation. The vulnerability is addressed via a disclosed vendor advisory.

## What to do

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

## Latest updates

- 2026-07-24: CVE-2026-59223: Open WebUI: `WEB_FETCH_FILTER_LIST` host allow/block filter bypassable via URL path and non-label-boundary matching (https://github.com/advisories/GHSA-qg3f-8x3j-ggf2)
- 2026-07-09: CVE-2026-59223: Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. (https://nvd.nist.gov/vuln/detail/CVE-2026-59223)

## Sources

- 2026-07-09 NVD: CVE-2026-59223: Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. https://nvd.nist.gov/vuln/detail/CVE-2026-59223
- 2026-07-24 GitHub Advisory Database: CVE-2026-59223: Open WebUI: `WEB_FETCH_FILTER_LIST` host allow/block filter bypassable via URL path and non-label-boundary matching https://github.com/advisories/GHSA-qg3f-8x3j-ggf2

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