Submit #895267: ramon-victor (https://github.com/ramon-victor) freegpt-webui latest (main/master branch) CWE-306 (Missing Authentication for Critical Function - endpointinfo

Titleramon-victor (https://github.com/ramon-victor) freegpt-webui latest (main/master branch) CWE-306 (Missing Authentication for Critical Function - endpoint
DescriptionUnauthenticated access to backend conversation API - Location: `server/backend.py:12`. The /backend-api/v2/conversation endpoint performs zero authentication or authorization checks. There is no login, no API key, no session validation, and no rate limiting. Additionally, the 'model' parameter from the client is never validated against the server-configured whitelist in server/config.py (models = {'gpt-3.5-turbo', 'gpt-3.5-turbo-16k-0613', 'gpt-3.5-turbo-16k', 'gpt-4'}). Any anonymous internet user can call this endpoint with any model name, consume upstream AI provider resources (including expensive models like gpt-4), and trigger jailbreak modes. The broken business rule is that access to the AI proxy service should be restricted and the selectable models should be limited to the configured whitelist. Exploitation: An attacker sends: POST /backend-api/v2/conversation with body {"model":"gpt-4","conversation_id":"a-b","jailbreak":"gpt-dan-11.0","meta":{"content":{"conversation":[],"internet_access":true,"parts":[{"role":"user","content":"..."}]}}}. No authentication is required. The attacker can repeatedly call this endpoint to exhaust rate limits on upstream free AI providers, degrade service for legitimate users, and access models not intended for public use. The attacker can also set jailbreak to 'gpt-dan-11.0' or 'gpt-evil' to bypass content safety.
Source⚠️ https://gist.github.com/Galaxync/15cb5d1bf6ab110f0cba91664ed511dd
User
 Galaxyn (UID 98388)
Submission07/19/2026 03:56 (2 months ago)
Moderation09/04/2026 16:42 (2 months later)
StatusAccepted
VulDB entry398805 [ramon-victor freegpt-webui up to 098db3dfeb41555c2ca9269df0f13e10ec1c35dc Backend Conversation API server/backend.py _conversation model missing authentication]
Points20

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