How severe is CVE-2025-66600?

CVE-2025-66600 has a CVSS 4.0 base score of 8.8, rated high severity.

Is CVE-2025-66600 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-66600?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-66600 have an EU (EUVD) identifier?

Yes. CVE-2025-66600 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-207173.

When was CVE-2025-66600 published?

CVE-2025-66600 was published on 2026-02-09 and last updated on 2026-06-17.

CVE-2025-66600

CVE-2025-66600 is a high-severity vulnerability with a CVSS 4.0 base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-358.

Key facts

Severity: High (CVSS 4.0 base score 8.8)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-207173
Weakness: CWE-358
Published: 2026-02-09
Last modified: 2026-06-17

Description

A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation. This product lacks HSTS (HTTP Strict Transport Security) configuration. When an attacker performs a Man in the middle (MITM) attack, communications with the web server could be sniffed. The affected products and versions are as follows: FAST/TOOLS (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) R9.01 to R10.04

Frequently asked questions

What is CVE-2025-66600?: A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation. This product lacks HSTS (HTTP Strict Transport Security) configuration. When an attacker performs a Man in the middle (MITM) attack, communications with the web server could be sniffed. The affected products and versions are as follows: FAST/TOOLS (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) R9.01 to R10.04
How severe is CVE-2025-66600?: CVE-2025-66600 has a CVSS 4.0 base score of 8.8, rated high severity.
Is CVE-2025-66600 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-66600?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-66600 have an EU (EUVD) identifier?: Yes. CVE-2025-66600 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-207173.
When was CVE-2025-66600 published?: CVE-2025-66600 was published on 2026-02-09 and last updated on 2026-06-17.

References

https://web-material3.yokogawa.com/1/39206/files/YSAR-26-0001-E.pdf

Other CWE-358 vulnerabilities

CVE-2018-0268 — Critical (CVSS 10.0): A vulnerability in the container management subsystem of Cisco Digital Network Architecture (DNA) Center could allow an…
CVE-2022-25152 — Critical (CVSS 9.9): The ITarian platform (SAAS / on-premise) offers the possibility to run code on agents via a function called procedures.…
CVE-2025-66603 — Critical (CVSS 9.8): A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation. The web server accepts the…
CVE-2025-62583 — Critical (CVSS 9.8): Whale Browser before 4.33.325.17 allows an attacker to escape the iframe sandbox in a dual-tab environment.
CVE-2023-3266 — Critical (CVSS 9.8): A non-feature complete authentication mechanism exists in the production application allowing an attacker to bypass all…
CVE-2019-6742 — Critical (CVSS 9.8): This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Samsung Galaxy S9…

Browse all CWE-358 vulnerabilities →