CVE-2025-66596Network attack vector

User redirection via unvalidated Host header

Published Feb 9, 2026 · Updated Feb 9, 2026

Open redirect in Yokogawa Electric Corporation FAST/TOOLS R9.01 through R10.04 allows remote attackers to redirect users via an invalid Host header. The web server fails to validate the HTTP Host header before redirect handling, allowing an attacker-supplied host to control the destination. No authentication is required; redirected users reach attacker-controlled content, with no reported direct data access or service interruption.

CVSS severity6.9
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in Yokogawa Electric Corporation FAST/TOOLS R9.01 through R10.04 allows remote attackers to redirect users via an invalid Host header. The web server fails to validate the HTTP Host header before redirect handling, allowing an attacker-supplied host to control the destination. No authentication is required; redirected users reach attacker-controlled content, with no reported direct data access or service interruption.

The record

CVE
CVE-2025-66596
Published
Feb 9, 2026
Updated
Feb 9, 2026
Vendor
Yokogawa Electric Corporation
Product
FAST/TOOLS
Classifications
CWE-601
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

6.9YokogawaGroupCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
5.8Yokogawa Electric CorporationCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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-601URL Redirection to Untrusted Site ('Open Redirect')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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