CVE-2026-42276

MEDIUMNVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
4.3
EG Score
4.3(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

May 8, 2026

Last Modified

May 12, 2026

Advisory Details (1)

Auto-updated May 8, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

IDOR in /chat/stop-chat-session allows any authenticated user to interrupt other users chat sessions · Advisory · onyx-dot-app/onyx · GitHub

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

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 147 total refreshes for this CVE.

  1. 2026-09-13 16:47 UTCEPSS rescore
  2. 2026-09-12 15:01 UTCEPSS rescore
  3. 2026-09-11 15:10 UTCOSV refresh
  4. 2026-09-11 14:53 UTCEPSS rescore
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  19. 2026-08-23 19:29 UTCEG score recompute
  20. 2026-08-23 00:19 UTCEPSS rescore
  21. 2026-08-21 23:49 UTCEPSS rescore
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  24. 2026-08-18 13:48 UTCEPSS rescore
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  1. 2026-08-17 11:59 UTCEG score recompute
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  3. 2026-08-16 04:40 UTCEG score recompute
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  6. 2026-08-14 03:16 UTCEG score recompute
  7. 2026-08-13 22:00 UTCEPSS rescore
  8. 2026-08-13 01:37 UTCEG score recompute
  9. 2026-08-12 13:51 UTCEPSS rescore
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  11. 2026-08-11 13:43 UTCEPSS rescore
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  17. 2026-08-08 16:37 UTCEPSS rescore
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  20. 2026-08-06 13:46 UTCEPSS rescore
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  22. 2026-08-05 19:17 UTCEPSS rescore
  23. 2026-08-04 15:10 UTCEPSS rescore
  24. 2026-08-04 10:38 UTCEPSS rescore
  25. 2026-08-04 03:38 UTCEG score recompute
  26. 2026-08-03 10:36 UTCEPSS rescore
  27. 2026-08-02 03:36 UTCEG score recompute
  28. 2026-08-01 04:16 UTCEPSS rescore
  29. 2026-07-30 16:28 UTCEPSS rescore
  30. 2026-07-30 01:30 UTCEPSS rescore
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  38. 2026-07-23 03:11 UTCEG score recompute
  39. 2026-07-22 14:08 UTCEPSS rescore
  40. 2026-07-21 15:24 UTCEPSS rescore
  41. 2026-07-20 17:08 UTCEPSS rescore
  42. 2026-07-19 14:31 UTCEPSS rescore
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  44. 2026-07-18 10:04 UTCEPSS rescore
  45. 2026-07-16 17:03 UTCEPSS rescore
  46. 2026-07-16 06:19 UTCOSV refresh
  47. 2026-07-15 16:57 UTCEPSS rescore
  48. 2026-07-15 02:00 UTCEPSS rescore
  49. 2026-07-13 22:30 UTCEPSS rescore
  50. 2026-07-13 06:13 UTCEPSS rescore
  51. 2026-07-12 05:46 UTCEPSS rescore
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  65. 2026-06-28 04:56 UTCEPSS rescore
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  67. 2026-06-25 13:49 UTCEPSS rescore
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  70. 2026-06-23 21:33 UTCEPSS rescore
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  73. 2026-06-21 14:56 UTCEPSS rescore
  74. 2026-06-21 14:56 UTCEPSS rescore
  75. 2026-06-21 01:59 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-42276?
CVE-2026-42276 is a medium vulnerability published on May 8, 2026. 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/{chatsessionid} 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…
When was CVE-2026-42276 disclosed?
CVE-2026-42276 was first published in the National Vulnerability Database on May 8, 2026, with the most recent update on May 12, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42276 actively exploited?
CVE-2026-42276 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.7% of all scored CVEs.
What is the CVSS score of CVE-2026-42276?
CVE-2026-42276 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-42276?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42276, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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