Is there a public exploit for CVE-2026-77776?

No public exploit for CVE-2026-77776 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-77776?

CVE-2026-77776 scores CVSS 9.3 (v4.0), rated critical. EPSS puts the chance of exploitation in the next 30 days at 0.61%.

What does CVE-2026-77776 affect?

CVE-2026-77776 affects Headroom Labs Headroom.

9.3 Critical

Headroom's LLM proxy derives the memory owner from the x-headroom-user-id request header.

CVE-2026-77776

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 resolvememoryidentity 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 HEADROOMPROXYTOKEN, 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.

Assessment

CVSS: 9.3 (v4.0)
Severity: Critical
EPSS: 0.61% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 21 August 2026
Last updated: 8 November 2026
Affected: Headroom Labs · Headroom
Assigner: VulnCheck

CVSS vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

At the source

EUVD (ENISA)

References

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