---
id: CVE-2026-77776
title: >-
  Headroom's LLM proxy derives the memory owner from the x-headroom-user-id
  request header
summary: >-
  Headroom's LLM proxy derives the memory owner from the x-headroom-user-id
  request header. The header is read directly at several points in
  headroom/proxy/handlers/openai.py, including the chat completion and websocket
  paths, and nothing …
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-639
published: '2026-08-21'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T20:40:01.933'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77776'
references:
  - url: 'https://github.com/headroomlabs-ai/headroom'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.py
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/identity.py
    label: disclosure@vulncheck.com
  - url: 'https://github.com/headroomlabs-ai/headroom/pull/2207'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/headroom-proxy-treats-the-client-supplied-x-headroom-user-id-header-as-an-authenticated-identity
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00345
epssPercentile: 0.28139
ingestedAt: '2026-09-09T21:22:45.546Z'
---

## Overview

Headroom's LLM proxy derives the memory owner from the x-headroom-user-id request header. The header is read directly at several points in headroom/proxy/handlers/openai.py, including the chat completion and websocket paths, and nothing binds the value to the caller. A client can therefore name another user's identifier and read or write that user's stored LLM memory. The fix introduces a single resolve_memory_identity seam in headroom/proxy/identity.py 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, 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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.