SimpleChat vulnerabilities

SimpleChat versions prior to 0.261.029 contain an XSS vulnerability in POST /api/group_documents/upload. An attacker with Owner, Admin, or DocumentManager privileges can persist a script that executes in the SimpleChat origin when another group member clicks Share, allowing access to victim-visible data and actions. This is fixed in version 0.261.029.

SimpleChat versions 0.261.003 and 0.261.027 contain an authorization ordering flaw in POST /api/user/plugins that allows an authenticated low-privileged user to bypass the _reject_non_admin_mcp_stdio check. This can lead to starting an attacker-selected OS process under the application service identity. This is fixed in version 0.261.031.

In SimpleChat prior to version 0.241.203, the authenticated GET /api/user/info/<user_id> and GET /api/user/profile-image/<user_id> endpoints lacked object-level authorization. A low-privilege authenticated user could supply an arbitrary user_id and read the corresponding Cosmos DB user-settings document, retrieving another user's email address, display name, and profile image.

In SimpleChat prior to version 0.241.206, several plugin validation routes lacked enforcement of authentication and authorization at runtime. Routes such as 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 were documented as requiring security but did not check if the user was logged in or had proper permissions. This allowed unauthenticated or unauthorized clients to invoke plugin validation, health check, and repair operations.