CVE-2026-77776Network attack vectorHinoki check available

Cross-user memory access via trusted identity header

Published Aug 21, 2026 · Updated Aug 21, 2026

Authorization bypass in Headroom before 0.36.1 allows remote attackers to read or write other users' stored LLM memory. Proxy handlers use the client-supplied x-headroom-user-id header directly as the memory-owner key without binding it to the caller. Network access is unauthenticated under the shipped Docker Compose configuration; the console command binds to loopback by default.

CVSS severity9.3
Critical
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Authorization bypass in Headroom before 0.36.1 allows remote attackers to read or write other users' stored LLM memory. Proxy handlers use the client-supplied x-headroom-user-id header directly as the memory-owner key without binding it to the caller. Network access is unauthenticated under the shipped Docker Compose configuration; the console command binds to loopback by default.

The record

CVE
CVE-2026-77776
Published
Aug 21, 2026
Updated
Aug 21, 2026
Vendor
Headroom Labs
Product
Headroom
Classifications
CWE-639, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <0.36.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Headroom Labs · Headroomversion=0 <0.36.1

Published CVSS scores

9.1VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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