CVE-2026-59223 Open WebUI vulnerability
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. Prior to 0.10.0, WEB_FETCH_FILTER_LIST matching compared configured host entries against URL strings and non-label-boundary suffixes, allowing path-based blocklist bypasses such as !internal.example.com in a URL path and sibling-domain matches that did not reflect the intended hostname policy. This issue is fixed in version 0.10.0.
Quick answer
Open WebUI should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Open WebUI <0.10.0
Fixed versions
- 0.10.0
How to fix it
CVE-2026-59223 affects Open WebUI before 0.10.0, where WEB_FETCH_FILTER_LIST matching compared entries against URL strings and unsafe suffixes, allowing hostname blocklist bypasses. Prioritize shared or internet-facing Open WebUI deployments because the issue can affect realtime sessions, model access, knowledge files, terminal proxy access, or sensitive settings depending on the endpoint. Upgrade Open WebUI to 0.10.0 or a later supported release. Disable web fetch for untrusted users or enforce outbound allowlists at the network layer until patched.
- Inventory all Open WebUI deployments, containers, workers, reverse proxies, realtime Socket.IO endpoints, terminal integrations, and configured model providers.
- Identify Open WebUI before 0.10.0 and schedule an upgrade to Open WebUI 0.10.0 or later for CVE-2026-59223.
- Upgrade Open WebUI to 0.10.0 or a later supported release, rebuild images, restart services, and clear stale application caches where applicable.
- Disable web fetch for untrusted users or enforce outbound allowlists at the network layer until patched.
- Review Open WebUI roles, verified-user status, model permissions, knowledge base permissions, terminal connections, Redis token revocation, and provider credentials for unnecessary exposure.
- Review application, reverse proxy, Socket.IO, terminal backend, and audit logs for suspicious endpoint use matching the affected workflow.
- If credential or data exposure is suspected, revoke sessions and API keys, rotate provider credentials and webhooks, remove malicious content, and preserve request logs before cleanup.
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Verify the fix
- Confirm every Open WebUI deployment reports version 0.10.0 or later and that old images or services are no longer running.
- Confirm web fetch filtering evaluates canonical hostnames with label-boundary matching and blocks path-based bypass payloads.
- Confirm authorization checks, token revocation, role checks, and response filtering match the intended policy for affected users and endpoints.
- Run focused regression checks against the affected endpoint and confirm unauthorized or malformed requests fail safely.
- Document patched image digests, configuration changes, credential rotation, log review, and test evidence.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-59223?
Open WebUI versions listed as affected should be reviewed: Open WebUI <0.10.0.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.