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Vulnerabilities

Vulnerability · CVE-2026-77776

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

Published Aug 21, 2026 · catalog updated Oct 15, 2026 · Headroom's LLM proxy derives

Check if you run it

No confirmed exploitation is on record for CVE-2026-77776. EPSS is 0.61%. Act only if a listed version of Headroom's LLM proxy derives is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Headroom's LLM proxy derives).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.61%
Remediation
Not established
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-77776

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-77776. EPSS is 0.61%. Act only if a listed version of Headroom's LLM proxy derives is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-639: Authorization Bypass Through User-Controlled Key. EPSS 0.61%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 21, 2026 · NIST NVD

    Detected

    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 r

  2. Oct 15, 2026 · NIST NVD

    Updated

    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 r

Sources

  • CVE.orgVulnerability recordCVE-2026-77776

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-77776

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.