Flowise, a drag‑and‑drop interface for building custom large language model flows, had a flaw that allowed any client setting the HTTP header x‑request‑from to "internal" to bypass all /api/v1/ authorization checks. Because an authenticated tenant session stores a browser cookie, a low‑privilege user could set that header and invoke internal administrative endpoints such as API key management, credential stores, and custom function execution, effectively escalating privileges. The CWE identified is 863 – Change Authentication Setting.

All installations of Flowise by FlowiseAI prior to version 3.0.13. The vulnerability affects the Flowise product regardless of deployment environment, as the header check is performed internally within the application.

The CVSS v3 score is 8.7, indicating a high level of severity. The EPSS score is less than 1 %, suggesting that exploitation is unlikely but not impossible. The vulnerability is not listed in the CISA KEV catalog. Attackers would need to authenticate to obtain a valid session cookie; the x‑request‑from header can then be spoofed in HTTP requests. The likely attack vector is remote via the web interface or API; the necessary prerequisites are access to any authenticated tenant session and the ability to manipulate HTTP headers, which are common capabilities for users with browser or API client access.