What is CVE-2026-42276?

CVE-2026-42276 is a medium-severity vulnerability in Onyx, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-05-08.

How severe is CVE-2026-42276?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Auth bypass in Onyx

CVE-2026-42276

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 authentic…

Vulnerability class: IDOR (Insecure Direct Object Reference)

EPSS: 0.000 (15.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.

Affected products

Onyx
Onyx-dot-app Onyx — versions < 3.0.9, >= 3.1.0, < 3.1.6, >= 3.2.0, < 3.2.6

Weakness classification (CWE)

CWE-639 — Authorization Bypass Through User-Controlled Key

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42276?: CVE-2026-42276 is a medium-severity vulnerability in Onyx, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-05-08.
How severe is CVE-2026-42276?: Medium severity. CVSS v3 base score is 4.3 out of 10.