A critical Server-Side Request Forgery vulnerability in Headroom allows unauthenticated attackers to redirect internal traffic to arbitrary external or internal targets.

This is a CWE-918 Server-Side Request Forgery vulnerability. The application utilizes the x-headroom-base-url header to determine the upstream destination for requests without performing adequate validation, allowing unauthenticated attackers to control the target of outbound server requests.

Successful exploitation allows an attacker to use the server as a proxy to probe internal networks or reach restricted external services. With a CVSS score of 8.6, this vulnerability poses a high risk of reconnaissance, unauthorized data retrieval, and potential bypass of network perimeter security, which could facilitate more complex attacks against internal infrastructure.

Immediate Action: Update the Headroom proxy software to version 0.36.1 or later immediately to incorporate the necessary input validation and security guards.

Proactive Monitoring: Review egress traffic logs from the Headroom proxy server to identify connections to unusual or unauthorized internal or external IP addresses.

Compensating Controls: Deploy egress filtering on the host machine to block outbound connections to sensitive internal segments and restrict traffic to known, authorized LLM service providers.

Public Exploit Available: No (exploit_available: false)

Given the potential for lateral movement and network reconnaissance, this vulnerability should be addressed immediately. Organizations relying on Headroom for LLM proxying must ensure their systems are updated to version 0.36.1 to close the SSRF vector.