CVE-2025-66601VulnerabilityPublished 9 Feb 2026

CVE-2025-66601: Yokogawa Electric FAST/TOOLS · CWE-358

Affects Yokogawa Electric FAST/TOOLSSource CVE Database V5

Not known to be exploited · CVSS 6.3 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

6.3Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: Present
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
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: Present: The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
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: 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

1. Monitor Yokogawa's official channels for patches or updates addressing this vulnerability and apply them promptly once available. 2. Implement strict Content-Type header enforcement on web servers and proxies serving FAST/TOOLS components to prevent browsers from performing content sniffing. 3. Use web application firewalls (WAFs) to detect and block suspicious requests that may attempt content sniffing attacks. 4. Segment industrial control networks from corporate IT networks to limit exposure and lateral movement opportunities. 5. Conduct regular security assessments and penetration tests focusing on web interfaces of industrial control systems. 6. Educate operational technology personnel about the risks of web-based attacks and ensure secure configuration of all web-facing components. 7. Employ network intrusion detection systems (NIDS) tuned to detect anomalous traffic patterns related to script injection or content sniffing attempts. 8. Restrict access to FAST/TOOLS web interfaces to trusted IP ranges and use VPNs or secure tunnels for remote access.

Description

CVE-2025-66601 is a medium-severity vulnerability in Yokogawa Electric Corporation's FAST/TOOLS software versions R9.01 to R10.04. The flaw arises because the product does not specify MIME types, enabling attackers to perform content sniffing attacks that could lead to execution of malicious scripts. This vulnerability does not require authentication or user interaction but has limited impact on confidentiality and integrity. No known exploits are currently in the wild. European organizations using FAST/TOOLS in critical industrial control systems could face risks of unauthorized script execution, potentially disrupting operations or enabling further attacks. Mitigation involves applying vendor patches when available, enforcing strict content-type headers via web server configurations, and network segmentation of affected systems. Countries with significant industrial automation sectors and Yokogawa customer bases, such as Germany, France, Italy, and the UK, are most likely to be impacted.

Impact

For European organizations, particularly those in industrial sectors such as manufacturing, energy, and utilities that rely on Yokogawa's FAST/TOOLS for supervisory control and data acquisition (SCADA), this vulnerability poses a risk of unauthorized script execution within their control environments. While the immediate impact on confidentiality and integrity is limited, successful exploitation could enable attackers to execute arbitrary scripts that may disrupt operations, manipulate process data, or serve as a foothold for further attacks. Given the critical nature of industrial control systems, even limited script execution can have cascading effects on availability and safety. The lack of required authentication and user interaction increases the risk of remote exploitation. European organizations with interconnected networks or insufficient segmentation between corporate and operational technology (OT) environments are particularly vulnerable. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often target industrial control systems for espionage or sabotage.

Summary

CVE-2025-66601 identifies a vulnerability classified under CWE-358 (Improperly Controlled Modification of Object Prototype Attributes) in Yokogawa Electric Corporation's FAST/TOOLS software, specifically versions R9.01 through R10.04. The root cause is the absence of explicit MIME type specification in the product's web components (packages RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB). This omission allows an attacker to exploit content sniffing behavior in browsers, where the browser attempts to infer the content type of a resource. By manipulating the content or headers, an attacker can cause the browser to execute malicious scripts embedded in responses that should otherwise be treated as non-executable content. The vulnerability is remotely exploitable without authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/AT:P/PR:N/UI:N). The partial impact on confidentiality and integrity suggests that while direct data theft or modification is limited, the execution of malicious scripts could lead to further compromise or disruption. The vulnerability affects critical industrial control system software widely used for monitoring and controlling industrial processes. No patches or exploits are currently publicly available, but the risk remains due to the nature of the flaw and the criticality of the affected systems.

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-358

Technical details

References

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