PraisonAI Browser Server allows unauthenticated WebSocket clients to hijack connected extension sessions

Summary

PraisonAI is a multi-agent teams system. In versions below 4.5.139 of PraisonAI and 1.5.140 of praisonaiagents, the browser bridge (praisonai browser start) is vulnerable to unauthenticated remote session hijacking due to missing authentication and a bypassable origin check on its /ws WebSocket endpoint. The server binds to 0.0.0.0 by default and only validates the Origin header when one is present, meaning any non-browser client that omits the header is accepted without restriction. An unauthenticated network attacker can connect, send a start_session message, and the server will route it to the first idle browser-extension WebSocket (effectively hijacking that session) and then broadcast all resulting automation actions and outputs back to the attacker. This enables unauthorized remote control of connected browser automation sessions, leakage of sensitive page context and automation results, and misuse of model-backed browser actions in any environment where the bridge is network-reachable. This issue has been fixed in versions 4.5.139 of PraisonAI and 1.5.140 of praisonaiagents.

Timeline

1. Apr 14, 2026, 3:05 AM UTCCVE published
2. Apr 14, 2026, 8:18 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: yes · Technical impact: total

3. Apr 14, 2026, 8:18 PM UTCRecord last updated

Affected versions

• MervinPraison PraisonAI

  fixed in 4.5.139

• MervinPraison praisonaiagents

  fixed in 1.5.140

• praisonaiagentsPyPI

  fixed in 1.5.140

• praisonaiPyPI

  fixed in 4.5.139

References 1