CVE-2026-77775

HighCVSS 8.6

Published: 21/08/2026(UTC)Translated: 21/08/2026(UTC)NVD NIST

Summary

Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. No check rejects loopback, link-local, or RFC 1918 destinations, so requests reach internal services and cloud metadata addresses. The Authorization header is forwarded unchanged to the caller-designated host. The reference docker-compose.yml exposes ports without required token, increasing risk.

Risk Assessment

An attacker can access internal services and cloud metadata, and also capture authorization headers, potentially leading to data leakage and privilege escalation.

Recommendation

Update Headroom to a patched version, configure a required token, and do not expose ports to the network without authentication.

Other vulnerabilities in Headroom

CVE-2026-77776Critical
Headroom's LLM proxy derives the memory owner from the x-headroom-user-id request header. The header is read directly at several points, and nothing binds the value to the caller. A client can name another user's identifier and read or write that user's stored LLM memory. The fix introduces a single resolve_memory_identity seam that honors the header only for loopback or allowlisted callers and otherwise binds the identity to the proxy-token fingerprint or the operating system user. The pip console script binds 127.0.0.1 by default, but the reference docker-compose.yml ships --host 0.0.0.0 with published ports and no required HEADROOM_PROXY_TOKEN, exposing the affected data-plane routes to the network without authentication.

Original NVD description (English source)

Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. _resolve_openai_upstream_base 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 as the upstream base; _select_passthrough_base_url in headroom/providers/proxy_routes.py reads the same header for the passthrough routes. No check rejects loopback, link-local, or RFC 1918 destinations, and because the component is a proxy the upstream response is returned to the caller, so the request reaches internal services and cloud metadata addresses and their responses are disclosed. The Authorization header accompanying the request is forwarded unchanged to the caller-designated host. The pip console script binds 127.0.0.1 by default, but the reference docker-compose.yml ships --host 0.0.0.0 with published ports and no required HEADROOM_PROXY_TOKEN, which the server itself warns about at startup, so a deployment following the shipped compose exposes the affected data-plane routes to the network without authentication.