CVE-2026-26118: How to Prove Your MCP Agent Wasn

CVE-2026-26118: How to Prove Your MCP Agent Wasn't Compromised Microsoft disclosed CVE-2026-26118 this week: a Server-Side Request Forgery (SSRF) vulnerability in Azure's Model Context Protocol server. CVSS 8.8. An attacker with network access can coerce your MCP server to contact internal services, steal credentials from metadata endpoints, and masquerade as your trusted agent. You'll patch it. But here's the problem nobody talks about: After the vulnerability window closes, how do you prove your agent didn't leak data? The Agent-in-the-Middle Problem Your LLM agent runs through an MCP server endpoint. The endpoint has elevated permissions — it can access internal APIs, databases, credential systems. Normally, your agent does legitimate work. Then the SSRF window opens. An attacker doesn't need to hijack your agent. They just need to trick the MCP server into making requests it shouldn't make. Those requests look like they came from your infrastructure. Your logs say "Agent connected.