CVE-2026-66720

7.1 highEPSS 0.3%

High (7.1). EPSS 0.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 4.0

7.1 high

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

6.5 medium

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 21% of CVEs (scores of 2026-10-31)
CWE: CWE-125
Published: 2026-07-30
Modified: 2026-09-03
Record from: the NVD, synced 2026-10-19

References

https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-211-10.json
https://www.cisa.gov/news-events/ics-advisories/icsa-26-211-10

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