CVE-2026-42276

Onyx: IDOR in /chat/stop-chat-session allows any authenticated user to interrupt other users chat sessions

State: Published
Severity: 4.3 Medium
Published: May 8, 2026
Updated: May 8, 2026
Reserved: Apr 26, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L	GitHub_M

Weaknesses

CWE-639 Authorization Bypass Through User-Controlled Key

Affected Products

Product	Versions
onyxonyx-dot-app	< 3.0.9Affected >= 3.1.0, < 3.1.6Affected >= 3.2.0, < 3.2.6Affected

References

https://github.com/onyx-dot-app/onyx/security/advisories/GHSA-rw6w-hp62-gc8w

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