CVE-2025-66600VulnerabilityPublished 9 Feb 2026

CVE-2025-66600: Yokogawa Electric FAST/TOOLS · CWE-358

Affects Yokogawa Electric FAST/TOOLSSource CVE Database V5

Not known to be exploited · CVSS 8.8 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

8.8High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 29% 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:H/VI:L/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: High
Vulnerable system integrity: Low
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: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to 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

To mitigate CVE-2025-66600, organizations should immediately configure HSTS on all FAST/TOOLS web servers to enforce HTTPS connections and prevent protocol downgrade attacks. This involves setting the Strict-Transport-Security HTTP header with an appropriate max-age directive and including subdomains if applicable. Network administrators should ensure that TLS is properly configured with strong cipher suites and certificates to secure communications. Regularly monitoring network traffic for signs of MITM attacks, such as unexpected certificate changes or anomalous traffic patterns, is recommended. Additionally, organizations should segment industrial control networks to limit exposure and restrict access to FAST/TOOLS interfaces. Applying any vendor-provided updates or patches once available is critical. Finally, conducting security awareness training for personnel and implementing intrusion detection systems tailored for industrial environments can help detect and respond to exploitation attempts.

Description

CVE-2025-66600 is a high-severity vulnerability in Yokogawa Electric Corporation's FAST/TOOLS software versions R9.01 through R10.04. The issue stems from the lack of HTTP Strict Transport Security (HSTS) configuration, which exposes communications to interception via man-in-the-middle (MITM) attacks. This vulnerability allows attackers to sniff sensitive data transmitted between clients and the web server. Exploitation requires no authentication or user interaction and can be performed remotely over the network. Although no known exploits are currently in the wild, the vulnerability poses a significant risk to confidentiality. European organizations using FAST/TOOLS in critical industrial control or SCADA environments could face data breaches or operational disruptions. Mitigation involves enabling HSTS on the web server, enforcing HTTPS connections, and monitoring network traffic for suspicious activity. Countries with substantial industrial automation sectors and Yokogawa customer bases, such as Germany, France, Italy, and the UK, are most likely to be affected.

Impact

For European organizations, especially those operating critical infrastructure or industrial control systems using Yokogawa FAST/TOOLS, this vulnerability poses a substantial risk. The potential impact includes unauthorized disclosure of sensitive operational data, which could lead to industrial espionage, sabotage, or disruption of manufacturing and utility services. Confidentiality breaches could expose proprietary process information or credentials, facilitating further intrusions. Given the critical role of FAST/TOOLS in supervisory control and data acquisition (SCADA) environments, exploitation could indirectly affect system integrity and availability if attackers leverage intercepted data to launch subsequent attacks. The lack of authentication or user interaction required for exploitation increases the threat surface. European industries such as energy, manufacturing, and transportation that rely on Yokogawa solutions may face operational disruptions, regulatory compliance issues, and reputational damage if this vulnerability is exploited.

Summary

CVE-2025-66600 identifies a security weakness in Yokogawa Electric Corporation's FAST/TOOLS software, specifically versions R9.01 through R10.04, which are used for industrial automation and control systems. The vulnerability is classified under CWE-358, indicating a failure to enforce HTTP Strict Transport Security (HSTS). HSTS is a web security policy mechanism that forces browsers to interact with servers only over secure HTTPS connections, preventing downgrade attacks and cookie hijacking. The absence of HSTS means that an attacker positioned as a man-in-the-middle (MITM) can intercept and sniff HTTP communications between clients and the FAST/TOOLS web server. This interception can lead to exposure of sensitive operational data or credentials transmitted in plaintext or over insecure channels. The CVSS 4.0 base score of 8.8 reflects the high severity, with attack vector being network-based, no required privileges or user interaction, and a high impact on confidentiality. The vulnerability affects multiple FAST/TOOLS packages including RVSVRN, UNSVRN, HMIWEB, FTEES, and HMIMOB, which are components typically involved in human-machine interface (HMI) and supervisory control. No patches or exploits are currently reported, but the risk remains significant due to the critical nature of the affected systems and the ease of exploitation. The vulnerability's exploitation could compromise the integrity of industrial control processes by leaking sensitive data or enabling further attacks.

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, 13:19 UTC

WeaknessesCWE-358

Technical details

References

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