Miggo at BlackHat 2026!
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Miggo AIGenerate vendor-ready rules for the observed attack patterns, plus reasoning and safe deployment guidance
| Package Name | Ecosystem | Vulnerable Versions | First Patched Version |
|---|---|---|---|
| github.com/googleapis/mcp-toolbox | go | < 1.2.0 | 1.2.0 |
Miggo AIRoot Cause AnalysisThe vulnerability exists within the sseHandler function in internal/server/mcp.go. This function, which manages Server-Sent Events (SSE) connections, was hardcoded to set the Access-Control-Allow-Origin HTTP header to *. This permissive CORS policy allows any web page, regardless of its origin, to make requests to the SSE endpoint. This flaw makes the application susceptible to DNS rebinding attacks. An attacker could host a malicious website that, after being visited by a user, could make requests to the user's local MCP Toolbox instance. The browser would allow these requests due to the wildcard CORS policy, enabling the attacker to potentially execute commands and exfiltrate data through the SSE connection. The fix involves removing the line that sets the insecure header, thus enforcing the intended security policies configured through allowed-origins and allowed-hosts flags.
