CVE-2026-42276 — Onyx: IDOR in /chat/stop-chat-session allows any authenticated user to interrupt other users chat sessions
Onyx is an open-source AI platform. Prior to versions 3.0.9, 3.1.6, and 3.2.6, the POST /chat/stop-chat-session/{chat_session_id} endpoint lets any authenticated user stop any o…
Published: 2026-05-08 · CVSS: 4.3 · CVSS 3.1
Onyx is an open-source AI platform. Prior to versions 3.0.9, 3.1.6, and 3.2.6, the POST /chat/stop-chat-session/{chat_session_id} endpoint lets any authenticated user stop any other user's active chat session. The endpoint checks authentication but never verifies the session belongs to the caller. An attacker who knows a chat session UUID can kill another user's LLM generation mid-stream. This issue has been patched in versions 3.0.9, 3.1.6, and 3.2.6.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7