SEPTEMBER 19, 2026
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Case File

CVE-2026-77775

HIGH · CVSS 8.6 EPSS 0.36% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-21 · Last synced 2026-09-18

CyberRota Analysis

AI-Generated

The vulnerability in Docker's Headroom LLM proxy allows an attacker to manipulate the x-headroom-base-url request header, potentially directing requests to internal services or cloud metadata addresses without proper validation. This can lead to unauthorized exposure of sensitive data, including the Authorization header, as the proxy forwards requests without authentication. Organizations using Docker with the default configurations should prioritize addressing this issue to mitigate the risk of data leakage and unauthorized access to internal resources.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-77775
Severity
HIGH
CVSS
8.6
EPSS
0.36%
Docker

Original NVD Description

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.