CVE-2026-66276

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory published 2026-08-05. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

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

An authenticated attacker can craft a disposition frame with large or illegal ranges causing excessive CPU usage due to naive range handling, leading to denial of service.

This issue affects Apache Qpid Proton-J: through 0.34.1.

Users are recommended to upgrade to version 0.35.0, which fixes the issue.

CVSS v3
6.5
EG Score
6.5(high)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
35%
KEV
Not listed

Published

August 5, 2026

Last Modified

August 7, 2026

Advisory Details (2)

Auto-updated Aug 6, 2026
No patch confirmed yet.
generic

oss-security - CVE-2026-66276: Apache Qpid Proton-J: Unbounded disposition range handling can lead to denial of service

http://www.openwall.com/lists/oss-security/2026/08/04/12
generic
https://lists.apache.org/thread/14nj0lpsqpnd3q0hw0t0tw44qvdo1jc2

Vendor Advisories for CVE-2026-66276(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 17× in last 7d / 50× 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.

  1. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 10:08 UTCEG score recompute
  3. 2026-08-20 10:08 UTCGHSA enrichment
  4. 2026-08-19 17:04 UTCEPSS rescore
  5. 2026-08-19 08:23 UTCEG score recompute
  6. 2026-08-19 08:23 UTCGHSA enrichment
  7. 2026-08-18 13:48 UTCEPSS rescore
  8. 2026-08-18 06:38 UTCEG score recompute
  9. 2026-08-18 06:37 UTCGHSA enrichment
  10. 2026-08-17 13:47 UTCEPSS rescore
  11. 2026-08-17 04:52 UTCEG score recompute
  12. 2026-08-17 04:52 UTCGHSA enrichment
  13. 2026-08-16 14:56 UTCEPSS rescore
  14. 2026-08-16 03:07 UTCEG score recompute
  15. 2026-08-16 03:07 UTCGHSA enrichment
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-15 01:22 UTCGHSA enrichment
  18. 2026-08-13 23:37 UTCEG score recompute
  19. 2026-08-13 23:37 UTCGHSA enrichment
  20. 2026-08-13 22:00 UTCEPSS rescore
  21. 2026-08-12 21:51 UTCEG score recompute
  22. 2026-08-12 21:51 UTCGHSA enrichment
  23. 2026-08-12 13:51 UTCEPSS rescore
  24. 2026-08-11 20:06 UTCEG score recompute
  25. 2026-08-11 20:06 UTCGHSA enrichment
Show 25 more
  1. 2026-08-11 00:00 UTCEPSS rescore
  2. 2026-08-10 18:21 UTCGHSA enrichment
  3. 2026-08-09 16:36 UTCEG score recompute
  4. 2026-08-09 16:36 UTCGHSA enrichment
  5. 2026-08-09 13:47 UTCEPSS rescore
  6. 2026-08-08 16:37 UTCEPSS rescore
  7. 2026-08-08 14:51 UTCEG score recompute
  8. 2026-08-08 14:51 UTCGHSA enrichment
  9. 2026-08-07 13:05 UTCEG score recompute
  10. 2026-08-07 13:05 UTCGHSA enrichment
  11. 2026-08-06 16:32 UTCEG score recompute▲ 6.50
  12. 2026-08-06 16:32 UTCGHSA enrichment
  13. 2026-08-06 16:30 UTCNVD updateCVSS v3 → 6.5 · severity → MEDIUM
  14. 2026-08-06 16:06 UTCEG score recompute▼ 6.50
  15. 2026-08-06 16:06 UTCGHSA enrichment
  16. 2026-08-06 16:05 UTCNVD update
  17. 2026-08-06 15:32 UTCEG score recompute▲ 6.50
  18. 2026-08-06 15:32 UTCGHSA enrichment
  19. 2026-08-06 15:31 UTCMITRE cvelistV5CVSS v3 → 6.5 · severity → MEDIUM
  20. 2026-08-06 13:47 UTCEPSS rescore
  21. 2026-08-05 19:17 UTCEPSS rescore
  22. 2026-08-05 19:17 UTCEPSS rescore
  23. 2026-08-05 07:19 UTCNVD update
  24. 2026-08-05 06:20 UTCEG score recompute
  25. 2026-08-05 06:20 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-66276?
CVE-2026-66276 is a medium vulnerability published on August 5, 2026. An authenticated attacker can craft a disposition frame with large or illegal ranges causing excessive CPU usage due to naive range handling, leading to denial of service. This issue affects Apache Qpid Proton-J: through 0.34.1. Users are recommended to upgrade to version 0.35.0, which fixes the…
When was CVE-2026-66276 disclosed?
CVE-2026-66276 was first published in the National Vulnerability Database on August 5, 2026, with the most recent update on August 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66276 actively exploited?
CVE-2026-66276 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 64.6% of all scored CVEs.
What is the CVSS score of CVE-2026-66276?
CVE-2026-66276 has a CVSS v3.1 base score of 6.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-66276?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66276, 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.

Dependency Blast Radius

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