Answer in brief
CVE-2026-77776 records a Critical severity (CVSS 9.1) vulnerability in Headroom Proxy Treats the Client-Supplied x-headroom-user-id Header as an Authenticated Identity. The current sources do not mark it as known exploited. The current feed maps Headroom Labs/Headroom (generic), Headroom Labs/headroom-ai (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Headroom Labs/Headroom (generic), Headroom Labs/headroom-ai (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Headroom Labs/Headroomgeneric | >=0 <0.36.1 | 0.36.1 |
| Headroom Labs/headroom-aigeneric | >=0 <0.36.1 | 0.36.1 |
Published upstream
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 21, 2026
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.
Quoted source text, attributed separately from HOL analysis.