What is the CVSS score of CVE-2026-57206?

CVE-2026-57206 has a CVSS 3.1 base score of 8.6 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L. EPSS exploitation probability: 0.9%.

Which versions of Simplechat are affected by CVE-2026-57206?

Microsoft SimpleChat versions prior to 0.241.206 contain a critical authentication bypass allowing unauthenticated remote attackers to invoke administrative functions including plugin validation,…. A patch is available.

How to fix or mitigate CVE-2026-57206?

Within 24 hours, audit all internet-exposed SimpleChat instances and document network topology; immediately implement network-level access restrictions to administrative endpoints using firewall rules or Web Application Firewall (WAF) policies. Within 7 days, deploy authentication proxy or reverse proxy with mandatory authentication for admin endpoints, and enable detailed logging of all access attempts to administrative functions. Within 30 days, contact Microsoft for upgrade guidance and prepare for immediate deployment of SimpleChat 0.241.206 or later once released, implementing comprehensive access controls during deployment to prevent similar bypasses.

Simplechat CVE-2026-57206

EUVD-2026-44942 HIGH

Missing Authentication for Critical Function (CWE-306)

2026-07-16 GitHub_M

Authentication Bypass Microsoft Simplechat

8.6

CVSS 3.1 · Vendor: GitHub_M

Severity by source

Vendor (GitHub_M) PRIMARY

8.6 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

Primary rating from Vendor (GitHub_M) · only source for this CVE.

CVSS VectorVendor: GitHub_M

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

Low

Lifecycle Timeline

Patch available

Jul 16, 2026 - 17:03 EUVD

Source Code Evidence Fetched

Jul 16, 2026 - 15:52 vuln.today

Analysis Generated

Jul 16, 2026 - 15:52 vuln.today

CVE Published

Jul 16, 2026 - 15:17 cve.org

HIGH 8.6

DescriptionCVE.org

SimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. Prior to 0.241.206, several plugin validation routes in application/single_app/plugin_validation_endpoint.py, including POST /api/admin/plugins/test-instantiation, GET /api/admin/plugins/health-check/<plugin_name>, POST /api/admin/plugins/repair/<plugin_name>, and POST /api/plugins/validate, relied on @swagger_route(security=get_auth_security()) documentation without enforcing @login_required, @user_required, or @admin_required at runtime, allowing unauthenticated or unauthorized clients to invoke plugin validation, health, and repair behavior. This issue is fixed in version 0.241.206.

AnalysisAI

Missing authentication in Microsoft SimpleChat (prior to 0.241.206) lets remote, unauthenticated clients invoke administrative plugin validation, health-check, and repair endpoints that were documented as protected but never enforced authentication at runtime. Any network-reachable attacker can trigger plugin instantiation, health probing, and repair actions without login or admin rights. No public exploit identified at time of analysis, and the CVE is not listed in CISA KEV.