CVE-2026-105798
HighCVSS 8.7Summary
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.
Risk Assessment
The risk involves execution of malicious script in the application context, potentially leading to data theft and unauthorized actions in the user's session.
Recommendation
Upgrade SimpleChat to version 0.261.029 or later and implement proper filename encoding.
Other vulnerabilities in SimpleChat
See all- CVE-2026-105797High
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.
- CVE-2026-57205Medium
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.
- CVE-2026-57206High
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.
Original NVD description (English source)
SimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. Prior to 0.261.029, POST /api/group_documents/upload stores an attacker-controlled group document filename that group_workspaces.html later interpolates into inline Share event handlers. The escapeGroupHtml function leaves apostrophes unchanged, while escapeHtml produces an HTML entity that the browser decodes before JavaScript evaluation, so either path permits the filename to terminate the handler string. An authenticated group Owner, Admin, or DocumentManager can persist script that executes in the SimpleChat origin when another group member clicks Share, allowing access to victim-visible data and actions with the victim session. This issue is fixed in version 0.261.029.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS