CVE-2025-66602VulnerabilityPublished 9 Feb 2026

CVE-2025-66602: Yokogawa Electric FAST/TOOLS · CWE-291

Affects Yokogawa Electric FAST/TOOLSSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

6.9Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Yokogawa Electric CorporationFAST/TOOLS	Affected ≥ R9.01, ≤ R10.04	Fixed in–

AI-suggested

1. Implement strict network segmentation to isolate FAST/TOOLS systems from general IT and internet-facing networks, reducing exposure to random IP scanning worms. 2. Restrict access to FAST/TOOLS web servers by enforcing IP whitelisting and firewall rules that limit connections to trusted management networks only. 3. Deploy intrusion detection and prevention systems (IDS/IPS) to monitor for unusual scanning or access patterns targeting FAST/TOOLS IP addresses. 4. Enforce strong authentication mechanisms at the network perimeter and within the industrial control system environment, supplementing or replacing IP-based access controls. 5. Regularly audit and update FAST/TOOLS configurations to disable unnecessary services and ensure minimal exposure. 6. Maintain up-to-date asset inventories to quickly identify and isolate vulnerable FAST/TOOLS instances. 7. Engage with Yokogawa Electric Corporation for updates on patches or security advisories and plan for timely application once available. 8. Conduct employee training on recognizing and responding to potential intrusion attempts targeting industrial control systems. 9. Consider deploying network anomaly detection tools specialized for industrial protocols to detect early signs of exploitation attempts.

Description

CVE-2025-66602 is a medium-severity vulnerability in Yokogawa Electric Corporation's FAST/TOOLS SCADA system versions R9.01 to R10.04. The flaw arises because the web server accepts access by IP address without sufficient authentication, enabling potential unauthorized access. This weakness could be exploited by a worm that randomly scans IP addresses to intrude into networks running the affected FAST/TOOLS packages (RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB). The vulnerability does not require user interaction or privileges and can be exploited remotely over the network, potentially compromising confidentiality. No known exploits are currently in the wild, and no patches have been published yet. European organizations using FAST/TOOLS in critical infrastructure sectors such as energy, manufacturing, or utilities may face increased risk, especially in countries with significant Yokogawa deployments. Mitigation should focus on network segmentation, restricting IP-based access, and monitoring for anomalous scanning activity. Given the critical role of FAST/TOOLS in industrial control, exploitation could disrupt operations or leak sensitive data, warranting proactive defense measures.

Impact

For European organizations, particularly those operating critical infrastructure such as energy production, utilities, manufacturing, and chemical processing, this vulnerability could lead to unauthorized access to industrial control systems managed by FAST/TOOLS. Such access may compromise the confidentiality of operational data, potentially exposing sensitive process information or intellectual property. While the vulnerability does not directly affect system integrity or availability, unauthorized access could serve as a foothold for further attacks, including lateral movement or deployment of malware within industrial networks. The risk is heightened by the potential for automated worms to scan and exploit vulnerable systems, increasing the likelihood of widespread compromise. Disruption or data leakage in critical sectors could have cascading effects on supply chains and public safety. European organizations with insufficient network segmentation or exposed FAST/TOOLS web servers are particularly vulnerable. The medium severity rating suggests a moderate but non-negligible risk, emphasizing the need for timely mitigation to prevent exploitation.

Summary

CVE-2025-66602 is a vulnerability classified under CWE-291 (Improper Authentication) found in Yokogawa Electric Corporation's FAST/TOOLS SCADA system, specifically affecting versions R9.01 through R10.04. The root cause is that the web server component of FAST/TOOLS accepts connections based solely on IP address without enforcing robust authentication mechanisms. This design flaw allows an unauthenticated attacker, potentially a worm that performs random IP address scanning, to gain unauthorized access to the system. The affected FAST/TOOLS packages include RVSVRN, UNSVRN, HMIWEB, FTEES, and HMIMOB, which are integral to the operation and monitoring of industrial processes. The vulnerability has a CVSS 4.0 base score of 6.9, indicating medium severity, with attack vector being network-based, no required privileges or user interaction, and low impact on confidentiality but no impact on integrity or availability. The lack of authentication combined with exposure to network scanning increases the risk of automated exploitation attempts. Although no exploits are currently known in the wild and no patches have been released, the vulnerability poses a significant risk to industrial control systems that rely on FAST/TOOLS for real-time monitoring and control. Attackers exploiting this flaw could gain unauthorized access to sensitive operational data or potentially manipulate system parameters if combined with other vulnerabilities or misconfigurations. The vulnerability highlights the importance of strong authentication and network access controls in industrial environments.

CWE-291Reliance on IP Address for Authentication (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product uses an IP address for authentication.
Architecture and Design
Use other means of identity verification that cannot be simply spoofed. Possibilities include a username/password or certificate.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.14.1 (opens in a new tab)
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
Attack patterns
Using Alternative IP Address Encodings (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

web-material3.yokogawa.com/1/39206/files/YSAR-26-0001-E.pdf (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 16 Feb 2026, 13:20 UTC

WeaknessesCWE-291

Technical details

References

Community reviews

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