Mesop vulnerabilities

Mesop is a Python-based UI framework for building web applications. Prior to 1.3.4, the unauthenticated /__csp__ endpoint passes attacker-controlled document-uri, blocked-uri, and violated-directive values to the csp_report handler in mesop/server/static_file_serving.py, which prints them to standard output without neutralizing terminal control sequences. When an operator views the resulting logs in an ANSI-capable terminal, injected ANSI or VT100 sequences can clear or reposition the display, hide text, or present forged messages, reducing the integrity of monitoring and incident-response output. This issue is fixed in version 1.3.4.

Mesop prior to version 1.3.3, when running in debug mode, exposes a GET /hot-reload endpoint whose unbounded loop depends on the user-supplied counter parameter. An unauthenticated attacker can send requests with high counter values, exhausting the worker pool and making the server unavailable. The attack requires minimal effort and leaves the server unresponsive until manually restarted.

Mesop, a Python-based UI framework, from version 1.2.3 to before version 1.2.5 contains an uncontrolled resource consumption vulnerability in the WebSocket implementation. An unauthenticated attacker can send a rapid succession of WebSocket messages, forcing the server to spawn an unbounded number of OS threads, leading to thread exhaustion and Out of Memory (OOM) errors, causing a complete Denial of Service (DoS).