CVE-2026-77775 Headroom Proxy Sends Upstream Requests to a Client-Supplied Base URL Without Address Validation

Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. resolveopenaiupstreambase in headroom/proxy/handlers/openai.py accepts the header value, requires only that it parse with an http or https scheme and a hostname, and returns it for use ...