Is CVE-2025-66603 actively exploited?

No active exploitation of CVE-2025-66603 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2025-66603 be exploited remotely?

Yes. CVE-2025-66603 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2025-66603?

CVE-2025-66603 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2025-66603

CWE-358Published: February 9, 2026· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

A vulnerability has been found in FAST/TOOLS provided by Yokogawa Electric Corporation.

The web server accepts

the OPTIONS method. An attacker could potentially use this information to carry

out other attacks.

The

affected products and versions are as follows: FAST/TOOLS (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) R9.01 to

R10.04

NVD Source

Risk Analysis

The web server in Yokogawa FAST/TOOLS accepts the OPTIONS method, which could provide information useful for further attacks. This critical vulnerability has a CVSS score of 9.8, indicating a high risk to system security. It is not currently listed in the CISA KEV.

The vulnerability is remotely exploitable with low complexity, but there is no known public exploit or active exploitation.

Recommended Action

Disable the OPTIONS method on the web server or update to a patched version of FAST/TOOLS.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2025-66603 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.