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PatchSiren cyber security CVE debrief

CVE-2025-66602 Yokogawa CVE debrief

CVE-2025-66602 is a Yokogawa FAST/TOOLS issue published by CISA on 2026-02-10. CISA’s advisory says the web server accepts access by IP address, and that a worm which randomly searches for IP addresses could potentially attack the system. The advisory rates the issue CVSS 5.3 (MEDIUM) with network attack vector and low confidentiality impact.

Vendor
Yokogawa
Product
FAST/TOOLS
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-02-10
Original CVE updated
2026-02-10
Advisory published
2026-02-10
Advisory updated
2026-02-10

Who should care

Organizations running Yokogawa FAST/TOOLS should care, especially OT/ICS teams responsible for server exposure, patching, segmentation, and perimeter controls. The risk is most relevant where the web server is reachable from untrusted or broadly accessible network zones.

Technical summary

The advisory describes a web server exposure condition in Yokogawa FAST/TOOLS. CISA provides CVSS v3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N, indicating a network-reachable issue that requires no privileges or user interaction and is scored for low confidentiality impact. The published remediation is to update to revision R10.04, apply patch software CS_e12787, and then apply R10.04 SP3.

Defensive priority

Medium. Patch promptly if FAST/TOOLS is deployed, and reduce exposure of the web server while updates are being planned or rolled out.

Recommended defensive actions

  • Update Yokogawa FAST/TOOLS to revision R10.04.
  • Apply patch software CS_e12787.
  • After applying the patch, apply R10.04 SP3.
  • Restrict access to the FAST/TOOLS web server using network segmentation and firewall rules.
  • Review OT/ICS hardening, whitelisting, and antivirus coverage as part of a broader security program.
  • Validate backup and recovery readiness before making changes.
  • Contact Yokogawa via the advisory’s support channel if you need help confirming remediation steps.

Evidence notes

All claims are drawn from the CISA CSAF advisory for ICSA-26-041-01 / CVE-2025-66602 and its listed remediations and references. The source states the web server accepts access by IP address and warns about worm activity that randomly searches for IP addresses. The CVSS vector provided in the advisory is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-66602 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-66602

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2025-66602 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-66602

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26-041-01.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-26-041-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/resources-tools/resources/ics-recommended-practices

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/publications/Cybersecurity_Best_Practices_for_Industrial_Control_Systems.pdf

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/topics/industrial-control-systems

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/uscert/sites/default/files/publications/emailscams0905.pdf

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/uscert/ncas/tips/ST04-014

    Reference

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.