CVE-2026-42276

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

Published May 8, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:onyx:onyx:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Onyx
Onyx onyx
Vendors & Products Onyx
Onyx onyx
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Onyx: IDOR in /chat/stop-chat-session allows any authenticated user to interrupt other users chat sessions
Weaknesses CWE-639
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 8, 2026, 12:57 PM
Reserved
Apr 26, 2026, 11:53 AM
Status
Analyzed
Published
May 8, 2026, 5:16 AM
Modified
Nov 11, 2026, 11:10 PM