The flaw resides in the handleGetSourceContext operation within the server component of debugmcp's mcp‑debugger, exploiting a path traversal weakness (CWE‑22). An attacker who can reach the server remotely can manipulate the input to the function to reference files outside the intended source context, potentially reading arbitrary files on the host. The publicly available exploit can be executed without authentication, enabling disclosure of sensitive data and compromising confidentiality.

Compiled files and runtimes of debugmcp's mcp‑debugger up to and including version 0.20.0 are vulnerable. The weakness is exercised through the src/server.ts module, affecting any environment where the server component is exposed to external network traffic.

The CVSS Base score of 5.3 indicates a moderate severity, but the absence of an EPSS rating prevents a precise assessment of current exploitation likelihood. The vulnerability is not listed in the CISA KEV catalog, yet a publicly documented exploit exists, pointing to a tangible risk. Since the attack vector is remote, any system running an exposed instance of the affected mcp‑debugger could be exploited by sending crafted requests to the handleGetSourceContext endpoint.