CVE-2026-77776 (GCVE-0-2026-77776)

Vulnerability from cvelistv5 – Published: 2026-08-21 11:22 – Updated: 2026-08-21 21:44
VLAI
Title
Headroom Proxy Treats the Client-Supplied x-headroom-user-id Header as an Authenticated Identity
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 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.
Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
9.3 (Critical)
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
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-21 21:18 UTC
CWE
  • CWE-639 - Authorization Bypass Through User-Controlled Key
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 6487 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Headroom Labs Headroom Affected: 0 , < 0.36.1 (semver)
Unaffected: 0.36.1 (semver)
guessed Create a notification for this product.
Date Public
2026-08-20 00:00
Credits
Gregory Tan (Grg0rry)
Show details on NVD website
To clipboard 

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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