What is CVE-2025-66602?

CVE-2025-66602 is a critical-severity vulnerability in Yokogawa Fast\/tools, classified under Reliance on IP Address for Authentication. CVSS score: 9.8/10. Published 2026-02-09.

How severe is CVE-2025-66602?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Yokogawa Fast\/tools

CVE-2025-66602

A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation. The web server accepts access by IP address. When a worm that randomly searches for IP addresses intrudes into the network, it could potentially be attacked by the worm. The affected products and versions are as follows: FAST/TOOLS (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) R9.01 to R10.04

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

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (27.2th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 27.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000

Affected products

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

Weakness classification (CWE)

CWE-291 — Reliance on IP Address for Authentication

References

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

Frequently asked questions

What is CVE-2025-66602?: CVE-2025-66602 is a critical-severity vulnerability in Yokogawa Fast\/tools, classified under Reliance on IP Address for Authentication. CVSS score: 9.8/10. Published 2026-02-09.
How severe is CVE-2025-66602?: Critical severity. CVSS v3 base score is 9.8 out of 10.