{"id":"CVE-2026-77776","state":"PUBLISHED","title":"Headroom Proxy Treats the Client-Supplied x-headroom-user-id Header as an Authenticated Identity","description":"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.","publishedAt":"2026-08-21T11:22:51.779Z","updatedAt":"2026-08-21T21:44:30.707Z","severity":{"score":9.3,"label":"Critical","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["Headroom Labs Headroom"],"affected":[{"vendor":"Headroom Labs","product":"Headroom","packageName":"headroom-ai","packageURL":"pkg:pypi/headroom-ai","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"0.36.1","versionType":"semver"},{"version":"0.36.1","status":"unaffected","versionType":"semver"}],"collectionURL":"https://pypi.org","repo":"https://github.com/headroomlabs-ai/headroom","programFiles":["headroom/proxy/handlers/openai.py","headroom/proxy/memory_handler.py","headroom/memory/easy.py"]}],"references":["https://github.com/headroomlabs-ai/headroom/pull/2207","https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.py","https://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/identity.py","https://github.com/headroomlabs-ai/headroom","https://www.vulncheck.com/advisories/headroom-proxy-treats-the-client-supplied-x-headroom-user-id-header-as-an-authenticated-identity"],"weaknesses":["CWE-639"],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/77xxx/CVE-2026-77776.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-77776","state":"PUBLISHED","datePublished":"2026-08-21T11:22:51.779Z","dateUpdated":"2026-08-21T21:44:30.707Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-08-21T11:09:25.553Z"},"containers":{"cna":{"title":"Headroom Proxy Treats the Client-Supplied x-headroom-user-id Header as an Authenticated Identity","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Headroom Labs","product":"Headroom","packageName":"headroom-ai","packageURL":"pkg:pypi/headroom-ai","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"0.36.1","versionType":"semver"},{"version":"0.36.1","status":"unaffected","versionType":"semver"}],"collectionURL":"https://pypi.org","repo":"https://github.com/headroomlabs-ai/headroom","programFiles":["headroom/proxy/handlers/openai.py","headroom/proxy/memory_handler.py","headroom/memory/easy.py"]}],"references":[{"url":"https://github.com/headroomlabs-ai/headroom/pull/2207","tags":["issue-tracking"],"name":"Pull Request #2207 addressing the assessment findings"},{"url":"https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.py","tags":["technical-description"],"name":"Header handling in the OpenAI proxy handler at v0.29.0"},{"url":"https://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/identity.py","tags":["technical-description"],"name":"resolve_memory_identity seam introduced by the fix"},{"url":"https://github.com/headroomlabs-ai/headroom","tags":["product"]},{"url":"https://www.vulncheck.com/advisories/headroom-proxy-treats-the-client-supplied-x-headroom-user-id-header-as-an-authenticated-identity","name":"VulnCheck Advisory: Headroom Proxy Treats the Client-Supplied x-headroom-user-id Header as an Authenticated Identity","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE","baseScore":9.1,"baseSeverity":"CRITICAL"}},{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":9.3,"baseSeverity":"CRITICAL"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-639","lang":"en","description":"Authorization Bypass Through User-Controlled Key","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-08-21T11:22:51.779Z"},"datePublic":"2026-08-20T00:00:00.000Z","credits":[{"lang":"en","value":"Gregory Tan (Grg0rry)","type":"finder"}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-21T21:18:54.351966Z","id":"CVE-2026-77776","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-21T21:44:30.707Z"}}]}}}