CyberRota Analysis
AI-GeneratedA vulnerability in the AshAi.Mcp.Server component of the ash-project allows attackers to exploit an origin validation error, enabling them to bypass DNS-rebinding protections and issue cross-site requests to a user's local MCP server. This can lead to unauthorized access and manipulation of sensitive data, posing a significant risk to users running affected versions of the ash_ai library (0.8.0 to before 1.0.0). Organizations utilizing this Java-based framework should prioritize patching to mitigate potential exploitation.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
Origin Validation Error vulnerability in ash-project ash_ai allows a malicious web page to bypass the MCP server's DNS-rebinding protection and issue cross-site requests to a user's local MCP server with that user's actor. In AshAi.Mcp.Server, with the default allowed_origins: nil, origin_allowed?/3 accepts an origin when uri.host == conn.host and the forwarded scheme is https. Both values are attacker-controlled: conn.host comes from the Host header and the scheme is read from the raw x-forwarded-proto header with no trusted-proxy check. Under DNS rebinding the browser sends the attacker's origin and a matching host, and page JavaScript may set X-Forwarded-Proto: https, so the check passes with no TLS or proxy involved. The fix trusts only localhost origins by default; other origins require an explicit allowed_origins allowlist. This issue affects ash_ai: from 0.8.0 before 1.0.0.