CVE-2026-66364

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 payload parser contains a boundary handling flaw that can be triggered by a single unauthenticated Layer 2 multicast frame on the process bus. When processing specific payload fields, an attacker controlled inner element length may exceed its enclosing length, causing the parser to over read by one byte. This out-of-bounds read reliably terminates the subscriber process, 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.
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
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

Vendor Advisories for CVE-2026-66364(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. 2026-08-20 23:58 UTCEG score recompute
  2. 2026-08-20 23:58 UTCGHSA enrichment
  3. 2026-08-20 22:56 UTCEPSS rescore
  4. 2026-08-20 01:50 UTCEG score recompute
  5. 2026-08-20 01:50 UTCGHSA enrichment
  6. 2026-08-19 17:04 UTCEPSS rescore
  7. 2026-08-19 03:41 UTCEG score recompute
  8. 2026-08-19 03:41 UTCGHSA enrichment
  9. 2026-08-18 13:48 UTCEPSS rescore
  10. 2026-08-18 05:31 UTCEG score recompute
  11. 2026-08-18 05:31 UTCGHSA enrichment
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-17 07:13 UTCEG score recompute
  14. 2026-08-17 07:13 UTCGHSA enrichment
  15. 2026-08-16 14:56 UTCEPSS rescore
  16. 2026-08-16 09:04 UTCEG score recompute
  17. 2026-08-16 09:04 UTCGHSA enrichment
  18. 2026-08-15 10:55 UTCEG score recompute
  19. 2026-08-15 10:55 UTCGHSA enrichment
  20. 2026-08-15 01:30 UTCEPSS rescore
  21. 2026-08-14 12:45 UTCEG score recompute
  22. 2026-08-14 12:45 UTCGHSA enrichment
  23. 2026-08-13 22:00 UTCEPSS rescore
  24. 2026-08-13 14:36 UTCGHSA enrichment
  25. 2026-08-12 16:27 UTCEG score recompute
Show 40 more
  1. 2026-08-12 16:27 UTCGHSA enrichment
  2. 2026-08-12 13:51 UTCEPSS rescore
  3. 2026-08-11 18:19 UTCEG score recompute
  4. 2026-08-11 18:18 UTCGHSA enrichment
  5. 2026-08-11 00:00 UTCEPSS rescore
  6. 2026-08-10 20:09 UTCGHSA enrichment
  7. 2026-08-09 22:00 UTCEG score recompute
  8. 2026-08-09 22:00 UTCGHSA enrichment
  9. 2026-08-09 13:47 UTCEPSS rescore
  10. 2026-08-08 23:51 UTCEG score recompute
  11. 2026-08-08 23:51 UTCGHSA enrichment
  12. 2026-08-08 16:37 UTCEPSS rescore
  13. 2026-08-08 01:41 UTCEG score recompute
  14. 2026-08-08 01:41 UTCGHSA enrichment
  15. 2026-08-07 03:32 UTCEG score recompute
  16. 2026-08-07 03:32 UTCGHSA enrichment
  17. 2026-08-06 13:47 UTCEPSS rescore
  18. 2026-08-06 05:23 UTCEG score recompute
  19. 2026-08-06 05:23 UTCGHSA enrichment
  20. 2026-08-05 19:17 UTCEPSS rescore
  21. 2026-08-05 19:17 UTCEPSS rescore
  22. 2026-08-05 07:14 UTCEG score recompute
  23. 2026-08-05 07:14 UTCGHSA enrichment
  24. 2026-08-04 15:10 UTCEPSS rescore
  25. 2026-08-04 10:39 UTCEPSS rescore
  26. 2026-08-04 09:04 UTCGHSA enrichment
  27. 2026-08-03 10:53 UTCEG score recompute
  28. 2026-08-03 10:53 UTCGHSA enrichment
  29. 2026-08-03 10:36 UTCEPSS rescore
  30. 2026-08-02 12:42 UTCEG score recompute
  31. 2026-08-02 12:42 UTCGHSA enrichment
  32. 2026-08-02 02:27 UTCEPSS rescore
  33. 2026-08-01 14:33 UTCEG score recompute
  34. 2026-08-01 14:33 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 22:46 UTCEG score recompute
  40. 2026-07-30 22:45 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66364?
CVE-2026-66364 is a medium vulnerability published on July 30, 2026. The GOOSE payload parser contains a boundary handling flaw that can be triggered by a single unauthenticated Layer 2 multicast frame on the process bus. When processing specific payload fields, an attacker controlled inner element length may exceed its enclosing length, causing the parser to over…
When was CVE-2026-66364 disclosed?
CVE-2026-66364 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-2026-66364 actively exploited?
CVE-2026-66364 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-2026-66364?
CVE-2026-66364 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-66364?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66364, 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

Explore the affected products and dependency analysis for CVE-2026-66364

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