OpenClaw < 2026.5.12 - Custom Header Leakage via MCP Streamable HTTP Cross-Origin Redirects

OpenClaw before 2026.5.12 contains an information disclosure vulnerability in streamable-http MCP servers that forwards operator-configured custom headers during cross-origin redirects. Attackers controlling or compromising an MCP endpoint can redirect requests to exfiltrate sensitive headers like API keys or tenant-routing credentials to attacker-controlled origins.