{"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":0.28136,"ingestedAt":"2026-09-09T21:22:45.546Z","slug":"CVE-2026-77776","body":"## Overview\n\nHeadroom'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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}