Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-66720

Severity CVSS v4.0:
HIGH
Type:
CWE-125 Out-of-bounds Read
Publication date:
30/07/2026
Last modified:
31/07/2026

Description

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

Impact

Vector 4.0
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 v4.0 Severity and Metrics:

Base Score: 7.10 HIGH
Vector: 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

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): None
Availability (VA): High
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0
7.10
Severity 4.0
HIGH
Vector 3.x
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 6.50 MEDIUM
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x
6.50
Severity 3.x
MEDIUM

References to Advisories, Solutions, and Tools