CVE-2026-59221: open-webui terminal proxy path traversal guard bypass via 9x encoded traversal

Severity: high (CVSS 7.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-07-09 · updated 2026-07-10
Weakness: CWE-22

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 products

open-webui: 0.9.6

References

https://github.com/open-webui/open-webui/commit/05098d25a58d03738e01c4e85e8852c3b4ad849c
https://github.com/open-webui/open-webui/pull/26050
https://github.com/open-webui/open-webui/releases/tag/v0.10.0
https://github.com/open-webui/open-webui/security/advisories/GHSA-frvj-c5qp-xj4w
https://github.com/open-webui/open-webui/security/advisories/GHSA-frvj-c5qp-xj4w

Get alerted when CVE-2026-59221 or the next vulnerability affects your stack