dbcve.org
Fast\/toolsApplication · Yokogawa

CVE-2025-66596

MEDIUM · 6.1 CVSS v3.1 Published 2026-02-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation. This product does not properly validate request headers. When an attacker inserts an invalid host header, users could be redirected to malicious sites. The affected products and versions are as follows: FAST/TOOLS (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) R9.01 to R10.04

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Host Header Injection vulnerability in Yokogawa FAST/TOOLS web applications (packages RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) spanning versions R9.01 to R10.04. The application fails to properly validate the Host request header, allowing attackers to manipulate HTTP requests and potentially redirect users to malicious external sites via open redirect attacks.

MitigationImplement strict Host header validation using an allowlist of permitted hostnames, enforce the use of security headers such as Strict-Transport-Security and Content-Security-Policy, and ensure the application validates the Host header against trusted sources before generating any redirects or constructing URLs.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Fast\/toolsApplication
Affected:>= r9.01, <= r10.04

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify FAST/TOOLS version
    Access the web interface and navigate to the system information or about page, or check version files in the installation directory. The version is typically displayed in the login page footer or under Help > About in the HMIWEB package.
    Affected if The installed version falls within R9.01 through R10.04 inclusive.
  2. Confirm web packages are active
    Verify that one or more of these web application packages are installed and running: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB. Check via the FAST/TOOLS administration console or Windows services panel.
    Affected if Any of the affected web packages (RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) are present and active.
  3. Check if HTTP web interface is accessible
    Attempt to access the FAST/TOOLS web URL over HTTP (port 80/8080) or HTTPS (port 443/8443). Confirm the web server is responding to requests.
    Affected if The web interface is accessible and responding to HTTP/HTTPS requests.
  4. Inspect redirect logic configuration
    Examine the web server configuration files (such as IIS web.config or Apache configuration) and application configuration for redirect rules or URL generation logic that uses the Host header. Look for patterns like Request.Url.Host or similar server variable usage.
    Affected if The application constructs URLs or performs redirects using the incoming Host header without validation against an allowlist.
  5. Verify security header presence
    Send a test request to the web interface and inspect the HTTP response headers for Strict-Transport-Security, Content-Security-Policy, and X-Frame-Options headers.
    Affected if Security headers are missing or not enforced, and the application relies on the Host header for redirect generation.

A user is affected if FAST/TOOLS version is between R9.01 and R10.04, the web interface is accessible, and the application uses the Host header for redirect or URL construction without validation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict Host header validation using an allowlist of permitted hostnames, enforce the use of security headers such as Strict-Transport-Security and Content-Security-Policy, and ensure the application validates the Host header against trusted sources before generating any redirects or constructing URLs.

Fix this in Fast\/tools Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,400
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-66596 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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