CVE-2025-66606Network attack vector

Script execution via improperly encoded URLs

Published Feb 9, 2026 · Updated Feb 9, 2026

Cross-site scripting in Yokogawa Electric Corporation FAST/TOOLS R9.01 through R10.04 allows remote attackers to execute scripts via crafted URLs. FAST/TOOLS fails to encode attacker-controlled URL content before placing it into web pages, allowing invalid identifier characters to become active browser content. Exploitation requires a user to open the crafted URL; the resulting script runs in the user’s browser context and can alter displayed page content.

CVSS severity2.1
Low
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Yokogawa Electric Corporation FAST/TOOLS R9.01 through R10.04 allows remote attackers to execute scripts via crafted URLs. FAST/TOOLS fails to encode attacker-controlled URL content before placing it into web pages, allowing invalid identifier characters to become active browser content. Exploitation requires a user to open the crafted URL; the resulting script runs in the user’s browser context and can alter displayed page content.

The record

CVE
CVE-2025-66606
Published
Feb 9, 2026
Updated
Feb 9, 2026
Vendor
Yokogawa Electric Corporation
Product
FAST/TOOLS
Classifications
CWE-86, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=R9.01 <=R10.04

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Yokogawa Electric Corporation · FAST/TOOLSversion=R9.01 <=R10.04

Published CVSS scores

3.4Yokogawa Electric CorporationCVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N
2.1Yokogawa Electric CorporationCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
9.6NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-86Improper Neutralization of Invalid Characters in Identifiers in Web Pages
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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