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Medium 4.3Published May 7, 2026

CVE-2026-42276Onyx: IDOR in /chat/stop-chat-session allows any authenticated user to interrupt other users chat sessions

Updated under an hour ago ()

Does this affect you?

It affects onyx-dot-app onyx and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
4.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE)
CWE-639
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
May 8, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
onyx-dot-app onyx
onyx_dot_app:onyx (from the name)
before 3.0.9; from 3.1.0, < 3.1.6; from 3.2.0, < 3.2.6
CNA record
onyx onyx
onyx:onyx
before 3.0.9; from 3.1.0 before 3.1.6; from 3.2.0 before 3.2.6
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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