CVE-2026-42276

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

MEDIUM
4.3
CVSS Score
Published: May 8, 2026 at 03:49 AM UTC
Updated: June 17, 2026 at 10:47 AM UTC
2 products affected across 2 vendorsOnyxOnyx

Using onyx by onyx-dot-app?

Get instant alerts when new vulnerabilities affect onyx - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM4.3
Exploit prediction
EPSS 0.3%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.0.93.1.0 ≤ v < 3.1.63.2.0 ≤ v < 3.2.6
v < 3.0.9v < 3.1.6v < 3.2.6
Affected range stops below 3.0.9, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.1.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.2.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

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

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-639

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card