CVE-2026-59221 is a high-severity (CVSS 7.7) Path Traversal vulnerability in open-webui. O3 Security confirms whether CVE-2026-59221 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
open-webui terminal proxy path traversal guard bypass via 9x encoded traversal
Real-World Exposure
open-webuiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.6 before 0.10.0, _sanitize_proxy_path in backend/open_webui/routers/terminals.py decoded proxy paths only eight times, allowing a nine-times percent-encoded ../ traversal value to pass normalization checks and be decoded by the upstream terminal server. This issue is fixed in version 0.10.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | open-webui | ≥ 0.9.6&&< 0.10.0 | 0.10.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for open-webui. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update open-webui to 0.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-59221 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-59221 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-59221. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-59221 in your dependencies?
O3 detects CVE-2026-59221 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.