CVE-2026-66720

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-31. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
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.

The GOOSE subscriber component improperly validates the UTC timestamp field in unauthenticated IEC 61850 GOOSE (EtherType 0x88B8) Layer-2 multicast messages. A specially crafted GOOSE frame containing an undersized timestamp field can trigger a heap out-of-bounds read during message processing, causing the process to crash and resulting in a denial-of-service condition.

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
7%
KEV
Not listed

Published

July 30, 2026

Last Modified

July 31, 2026

Advisory Details (2)

Auto-updated Jul 30, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

MZ Automation GmbH libiec61850 | CISA

MZ Automation GmbH libiec61850 | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/news-events/ics-advisories/icsa-26-211-10
generic

CSAF/csaf_files/OT/white/2026/icsa-26-211-10.json at develop · cisagov/CSAF · GitHub

https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-211-10.json

Vendor Advisories for CVE-2026-66720(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 22× in last 7d / 65× 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. 2026-08-21 03:39 UTCEG score recompute
  2. 2026-08-21 03:39 UTCGHSA enrichment
  3. 2026-08-20 22:56 UTCEPSS rescore
  4. 2026-08-20 05:21 UTCEG score recompute
  5. 2026-08-20 05:21 UTCGHSA enrichment
  6. 2026-08-19 17:04 UTCEPSS rescore
  7. 2026-08-19 07:01 UTCEG score recompute
  8. 2026-08-19 07:01 UTCGHSA enrichment
  9. 2026-08-18 13:48 UTCEPSS rescore
  10. 2026-08-18 08:42 UTCEG score recompute
  11. 2026-08-18 08:42 UTCGHSA enrichment
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-17 10:20 UTCEG score recompute
  14. 2026-08-17 10:20 UTCGHSA enrichment
  15. 2026-08-16 14:56 UTCEPSS rescore
  16. 2026-08-16 12:01 UTCEG score recompute
  17. 2026-08-16 12:01 UTCGHSA enrichment
  18. 2026-08-15 13:43 UTCEG score recompute
  19. 2026-08-15 13:43 UTCGHSA enrichment
  20. 2026-08-15 01:30 UTCEPSS rescore
  21. 2026-08-14 15:24 UTCEG score recompute
  22. 2026-08-14 15:24 UTCGHSA enrichment
  23. 2026-08-13 22:00 UTCEPSS rescore
  24. 2026-08-13 17:05 UTCGHSA enrichment
  25. 2026-08-12 18:45 UTCEG score recompute
Show 40 more
  1. 2026-08-12 18:45 UTCGHSA enrichment
  2. 2026-08-12 13:51 UTCEPSS rescore
  3. 2026-08-11 20:26 UTCEG score recompute
  4. 2026-08-11 20:26 UTCGHSA enrichment
  5. 2026-08-11 00:00 UTCEPSS rescore
  6. 2026-08-10 22:08 UTCGHSA enrichment
  7. 2026-08-09 23:49 UTCEG score recompute
  8. 2026-08-09 23:49 UTCGHSA enrichment
  9. 2026-08-09 13:47 UTCEPSS rescore
  10. 2026-08-09 01:31 UTCEG score recompute
  11. 2026-08-09 01:31 UTCGHSA enrichment
  12. 2026-08-08 16:37 UTCEPSS rescore
  13. 2026-08-08 03:12 UTCEG score recompute
  14. 2026-08-08 03:12 UTCGHSA enrichment
  15. 2026-08-07 04:53 UTCEG score recompute
  16. 2026-08-07 04:53 UTCGHSA enrichment
  17. 2026-08-06 13:47 UTCEPSS rescore
  18. 2026-08-06 06:34 UTCEG score recompute
  19. 2026-08-06 06:34 UTCGHSA enrichment
  20. 2026-08-05 19:17 UTCEPSS rescore
  21. 2026-08-05 19:17 UTCEPSS rescore
  22. 2026-08-05 08:15 UTCEG score recompute
  23. 2026-08-05 08:15 UTCGHSA enrichment
  24. 2026-08-04 15:10 UTCEPSS rescore
  25. 2026-08-04 10:39 UTCEPSS rescore
  26. 2026-08-04 09:55 UTCGHSA enrichment
  27. 2026-08-03 11:22 UTCEG score recompute
  28. 2026-08-03 11:22 UTCGHSA enrichment
  29. 2026-08-03 10:36 UTCEPSS rescore
  30. 2026-08-02 13:01 UTCEG score recompute
  31. 2026-08-02 13:01 UTCGHSA enrichment
  32. 2026-08-02 02:27 UTCEPSS rescore
  33. 2026-08-01 14:42 UTCEG score recompute
  34. 2026-08-01 14:42 UTCGHSA enrichment
  35. 2026-08-01 04:16 UTCEPSS rescore
  36. 2026-07-31 16:24 UTCEG score recompute
  37. 2026-07-31 16:23 UTCGHSA enrichment
  38. 2026-07-30 23:20 UTCEG score recompute
  39. 2026-07-30 23:12 UTCEG score recompute
  40. 2026-07-30 23:10 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-66720?
CVE-2026-66720 is a medium vulnerability published on July 30, 2026. The GOOSE subscriber component improperly validates the UTC timestamp field in unauthenticated IEC 61850 GOOSE (EtherType 0x88B8) Layer-2 multicast messages. A specially crafted GOOSE frame containing an undersized timestamp field can trigger a heap out-of-bounds read during message processing,…
When was CVE-2026-66720 disclosed?
CVE-2026-66720 was first published in the National Vulnerability Database on July 30, 2026, with the most recent update on July 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66720 actively exploited?
CVE-2026-66720 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 92.8% of all scored CVEs.
What is the CVSS score of CVE-2026-66720?
CVE-2026-66720 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-66720?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66720, 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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