CVE-2026-66005
Jan Local API Server CORS Origin Reflection via 0.0.0.0 Binding
Description
Jan through 0.8.4, fixed in commit 3e1c1e7, contains a CORS misconfiguration vulnerability in its local API server that allows network-adjacent attackers to bypass trusted host restrictions by exploiting the server's replacement of user-configured trusted hosts with a wildcard that reflects arbitrary origins with credentials. Attackers on the local network or using DNS rebinding can reach the unauthenticated OpenAI-compatible API to perform inference, enumerate models, invoke MCP tools, and read cross-origin responses.
INFO
Published Date :
July 24, 2026, 3:19 p.m.
Last Modified :
Oct. 24, 2026, 1:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-66005
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 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update the software to a version that includes commit 3e1c1e7.
- Apply vendor-provided patches or updates for the local API server.
- Review and restrict trusted host configurations carefully.
- Disable unnecessary API endpoints.
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-2026-66005.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-66005 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-2026-66005
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-2026-66005 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-66005 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. 24, 2026
Action Type Old Value New Value Added Translation Title: jan de janhq, Description: Jan hasta la 0.8.4, corregida en el commit 3e1c1e7, contiene una vulnerabilidad de mala configuración de CORS en su servidor API local que permite a atacantes adyacentes a la red eludir las restricciones de host de confianza explotando el reemplazo por parte del servidor de los hosts de confianza configurados por el usuario por un comodín que refleja orígenes arbitrarios con credenciales. Atacantes en la red local o que utilizan el reenlace de DNS pueden acceder a la API compatible con OpenAI no autenticada para realizar inferencia, enumerar modelos, invocar herramientas MCP y leer respuestas de origen cruzado. -
CVE Modified by [email protected]
Sep. 17, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/66xxx/CVE-2026-66005.json">CVE-2026-66005</a> Added Reference https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757 Added Reference https://github.com/janhq/jan/issues/8453 Added Reference https://github.com/janhq/jan/pull/8506 Added Reference https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection-via-binding Removed Reference https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757 Removed Reference https://github.com/janhq/jan/issues/8453 Removed Reference https://github.com/janhq/jan/pull/8506 Removed Reference https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection-via-binding -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 24, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-66005', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-24T15:32:21.328068Z'} -
New CVE Received by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/janhq/jan', 'vendor': 'janhq', 'product': 'jan', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '0.8.4'}, {'status': 'unaffected', 'version': '3e1c1e724f696620d89bb4a9cc18a380e0753757', 'versionType': 'git'}], 'packageURL': 'pkg:npm/jan-app', 'defaultStatus': 'unaffected'}] Added Description Jan through 0.8.4, fixed in commit 3e1c1e7, contains a CORS misconfiguration vulnerability in its local API server that allows network-adjacent attackers to bypass trusted host restrictions by exploiting the server's replacement of user-configured trusted hosts with a wildcard that reflects arbitrary origins with credentials. Attackers on the local network or using DNS rebinding can reach the unauthenticated OpenAI-compatible API to perform inference, enumerate models, invoke MCP tools, and read cross-origin responses. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/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:R/S:U/C:L/I:L/A:L Added CWE CWE-183 Added CWE CWE-942 Added Reference https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757 Added Reference https://github.com/janhq/jan/issues/8453 Added Reference https://github.com/janhq/jan/pull/8506 Added Reference https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection-via-binding