What is CVE-2025-66596?

CVE-2025-66596 is a medium-severity vulnerability in Yokogawa Fast\/tools, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2026-02-09.

How severe is CVE-2025-66596?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Open Redirect in Yokogawa Fast\/tools

CVE-2025-66596

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

Vulnerability class: Open Redirect

Published 2026-02-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (4.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 4.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Yokogawa Fast\/tools
Yokogawa Electric Corporation Fast/tools — versions R9.01

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

7168b535-132a-4efe-a076-338f829b2eb9 (Vendor Advisory)

Frequently asked questions

What is CVE-2025-66596?: CVE-2025-66596 is a medium-severity vulnerability in Yokogawa Fast\/tools, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2026-02-09.
How severe is CVE-2025-66596?: Medium severity. CVSS v3 base score is 6.1 out of 10.