PatchSiren

PatchSiren cyber security CVE debrief

CVE-2025-66600 Yokogawa CVE debrief

Yokogawa FAST/TOOLS is affected by a missing HTTP Strict Transport Security (HSTS) configuration in its web server. The supplied CISA advisory says a man-in-the-middle attack could allow an attacker to sniff communications. The issue is network-exploitable, scored CVSS 8.2 (HIGH), and should be prioritized for any exposed FAST/TOOLS deployment.

Vendor
Yokogawa
Product
FAST/TOOLS
CVSS
HIGH 8.2
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

OT/ICS operators, control-system administrators, and security teams responsible for Yokogawa FAST/TOOLS, especially where the web interface is reachable over enterprise, remote-access, or other untrusted networks.

Technical summary

CISA’s CSAF advisory ICSA-26-041-01 states that Yokogawa FAST/TOOLS lacks HSTS. In practical terms, clients are not forced to remain on HTTPS, weakening protection against interception of web traffic. The supplied CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N, indicating a remotely reachable issue with high confidentiality impact and limited integrity impact. Yokogawa’s remediation guidance is to update to revision R10.04, apply patch software CS_e12787, and then apply R10.04 SP3.

Defensive priority

High — prioritize for any FAST/TOOLS web server that is exposed beyond a tightly controlled management network.

Recommended defensive actions

  • Apply Yokogawa’s stated remediation path: update to revision R10.04, apply patch software CS_e12787, and then apply R10.04 SP3.
  • Limit access to the FAST/TOOLS web server to trusted management networks and required administrative paths only.
  • Verify that HTTPS-only access is enforced where supported and that HSTS is enabled after remediation.
  • Use segmentation, firewall rules, and other defense-in-depth controls to reduce the chance of interception on OT management traffic.
  • Follow CISA’s ICS recommended practices and vendor security-program guidance for patching, hardening, backup/recovery, whitelisting, and related controls.

Evidence notes

This debrief is based on the supplied CISA CSAF advisory for ICSA-26-041-01 / CVE-2025-66600 and the associated official reference links. The advisory explicitly says FAST/TOOLS lacks HSTS and that a MITM attacker could sniff web communications. The vendor remediation steps were taken directly from the advisory. The supplied enrichment does not mark this as a CISA KEV item.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-66600 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-66600

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

  • CVE-2025-66600 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-66600

    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.