CVE-2026-56400 open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation
Attackers can execute arbitrary code on open-webui instances by exploiting CORS misconfigurations and session validation flaws when an admin visits a malicious site.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-56400?
CVE-2026-56400 is a critical vulnerability in Openwebui Open Webui, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
open-webui before 0.3.14 contains a cross-origin resource sharing misconfiguration allowing arbitrary origins with allow_origins=* and authenticated requests to the /api/v1/functions endpoint. Attackers can execute arbitrary code on the openwebui instance by crafting malicious cross-site requests from attacker-controlled websites when an admin user visits them.
Weakness: CWE-613
Which versions are affected by CVE-2026-56400?
2 open source packages ship an affected version, including open-webui. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
open-webui PyPI | All versions | 0.3.33 |
open-webui PyPI | All versions | 0.3.33 |
Products include Openwebui Open Webui.
How do I fix CVE-2026-56400?
Upgrade open-webui to 0.3.33 or later.
Is CVE-2026-56400 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56400 exists.
Other vulnerabilities in Openwebui Open Webui
- CVE-2026-44551 Open WebUI: LDAP Empty Password Authentication Bypass
- CVE-2024-8017 Cross-site Scripting (XSS) in open-webui/open-webui
- CVE-2026-45672 Open WebUI: Jupyter code execution works despite `ENABLE_CODE_EXECUTION=false` — feature gate bypassed
- CVE-2026-87995 Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin
- CVE-2026-70492 Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
Sources
Also known as GHSA-6xcp-7mpr-m7wm, GHSA-m5hr-9f92-qvh9.