CVE-2026-77776
Headroom Proxy Treats the Client-Supplied x-headroom-user-id Header as an Authenticated Identity
Description
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.
INFO
Published Date :
Aug. 21, 2026, 12:16 p.m.
Last Modified :
Oct. 15, 2026, 7:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-77776
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 3.1 | CRITICAL | MITRE-CVE | ||||
| CVSS 4.0 | CRITICAL | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Validate incoming user IDs against allowed callers.
- Bind memory identity to proxy-token or OS user.
- Securely configure network exposure and authentication.
- Apply security patches from the vendor.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-77776.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-77776 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-77776
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-77776 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-77776 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 15, 2026
Action Type Old Value New Value Added Translation Title: Headroom Labs, Description: El proxy LLM de Headroom deriva el propietario de la memoria del encabezado de solicitud x-headroom-user-id. El encabezado se lee directamente en varios puntos en headroom/proxy/handlers/openai.py, incluyendo las rutas de completado de chat y websocket, y nada vincula el valor al llamador. Un cliente puede, por lo tanto, nombrar el identificador de otro usuario y leer o escribir la memoria LLM almacenada de ese usuario. La solución introduce una única costura resolve_memory_identity en headroom/proxy/identity.py que respeta el encabezado solo para llamadores de loopback o en lista blanca y de lo contrario vincula la identidad a la huella digital del token de proxy o al usuario del sistema operativo. El script de consola pip enlaza 127.0.0.1 por defecto, pero el docker-compose.yml de referencia se envía con --host 0.0.0.0 con puertos publicados y sin HEADROOM_PROXY_TOKEN requerido, sobre lo cual el propio servidor advierte al inicio, por lo que un despliegue siguiendo el compose enviado expone las rutas del plano de datos afectadas a la red sin autenticación. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 21, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-77776', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-21T21:18:54.351966Z'} -
New CVE Received by [email protected]
Aug. 21, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/headroomlabs-ai/headroom', 'vendor': 'Headroom Labs', 'product': 'Headroom', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.36.1', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '0.36.1', 'versionType': 'semver'}], 'packageURL': 'pkg:pypi/headroom-ai', 'packageName': 'headroom-ai', 'programFiles': ['headroom/proxy/handlers/openai.py', 'headroom/proxy/memory_handler.py', 'headroom/memory/easy.py'], 'collectionURL': 'https://pypi.org', 'defaultStatus': 'unaffected'}] Added Description 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Added CWE CWE-639 Added Reference https://github.com/headroomlabs-ai/headroom Added Reference https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.py Added Reference https://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/identity.py Added Reference https://github.com/headroomlabs-ai/headroom/pull/2207 Added Reference https://www.vulncheck.com/advisories/headroom-proxy-treats-the-client-supplied-x-headroom-user-id-header-as-an-authenticated-identity