What is the CVSS score of CVE-2025-66602?

CVE-2025-66602 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

How to fix or mitigate CVE-2025-66602?

Within 24 hours: Identify and inventory all FAST/TOOLS installations; restrict network access to the web server using firewall rules limiting connectivity to authorized IPs only; disable remote access if not operationally required. Within 7 days: Implement web application firewall (WAF) rules to block suspicious access patterns; conduct security assessment of affected systems; establish enhanced monitoring and logging. Within 30 days: Coordinate with Yokogawa for patch availability; plan and execute patching in controlled maintenance windows; validate remediation across all instances.

Fast Tools CVE-2025-66602

CRITICAL

Reliance on IP Address for Authentication (CWE-291)

2026-02-09 7168b535-132a-4efe-a076-338f829b2eb9

Information Disclosure Fast Tools Yokogawa

9.8

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-291 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V6 - Authentication IP-independent authentication
Impact	CVSS 9.8 — Yokogawa FAST/TOOLS is a major SCADA platform used in oil & gas, chemicals, and utilities. IP-based authentication is trivially spoofable.
Exploit ScenarioDerived	An attacker spoofs the IP address of an authorized workstation to bypass authentication on the FAST/TOOLS web interface, gaining access to SCADA monitoring and control functions.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Yokogawa FAST/TOOLS SCADA has a vulnerability in its web server component enabling unauthorized access to the industrial control monitoring system.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 9.8

Web server vulnerability in Yokogawa FAST/TOOLS SCADA enables unauthorized access.

RemediationAI

Apply Yokogawa patches. Implement stronger authentication. Segment SCADA networks.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Yokogawa FAST/TOOLS has a CWE-291 reliance on IP address for authentication vulnerability in its web server component, allowing attackers to bypass access controls.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation.

The web server accepts access by IP address. When a worm that randomly searches for IP addresses intrudes into the network, it could potentially be attacked by the worm.

The affected products and versions are as follows: FAST/TOOLS (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) R9.01 to R10.04

Executive ViewAI

Why It Matters

A critical vulnerability in Yokogawa FAST/TOOLS web server allows unauthorized access via IP-based authentication bypass, potentially exposing industrial control systems to remote attackers. Organizations using this platform face immediate risk of system compromise, data theft, and operational disruption without available patches.

Business Impact: Severe

Compensating Controls

Implement strict network segmentation isolating FAST/TOOLS servers; deploy WAF with IP reputation filtering and rate limiting; restrict web server access via firewall to authorized IP ranges only; disable unnecessary web server features; enforce multi-factor authentication where supported; enable comprehensive audit logging and real-time alerting; consider air-gapping critical systems until patch is available; monitor Yokogawa security advisories for patch release.

Threat Intelligence Overview

EPSS Score

0.1%

Top 82% exploitable

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC No

EPSS 0.1%

Patch available No

Active threat No

Deciding rule

CRITICAL severity

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Out-of-Cycle

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +49

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.