# CVE-2025-66598: Weak cryptography in FAST/TOOLS

> An attacker can decrypt communications with the web server due to support for old SSL/TLS versions in Yokogawa FAST/TOOLS.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Feb 2026
- **Updated:** 9 Feb 2026
- **Also known as:** GHSA-vwj8-79vf-v875

## What is CVE-2025-66598?

CVE-2025-66598 is a high-severity vulnerability in Yokogawa Electric Corporation FAST/TOOLS, published on 9 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

This product supports
old SSL/TLS versions, potentially allowing an attacker to decrypt
communications with the web server.

The
affected products and versions are as follows: FAST/TOOLS (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB) R9.01 to
R10.04

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2025-66598?

It affects 1 product.


Products: Yokogawa Fast\/Tools.

## How do I fix CVE-2025-66598?

No fix has been published for CVE-2025-66598 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-66598 being exploited?

There is no known exploitation of CVE-2025-66598 in the wild and no public exploit code.

## Other vulnerabilities in Yokogawa Electric Corporation FAST/TOOLS

- [CVE-2025-66597](https://insights.sbomify.com/CVE-2025-66597/): Weak cryptography in FAST/TOOLS (high 8.8)
- [CVE-2025-66608](https://insights.sbomify.com/CVE-2025-66608/): Path traversal in FAST/TOOLS (high 8.7)
- [CVE-2025-66594](https://insights.sbomify.com/CVE-2025-66594/): Information disclosure in FAST/TOOLS (medium 6.9)
- [CVE-2025-66596](https://insights.sbomify.com/CVE-2025-66596/): Open redirect in FAST/TOOLS (medium 6.9)
- [CVE-2025-66602](https://insights.sbomify.com/CVE-2025-66602/): Missing authorization in FAST/TOOLS (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-66598 and fix it if it is affected.

What it is: CVE-2025-66598 is a high-severity vulnerability in Yokogawa Electric Corporation FAST/TOOLS, published on 9 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-66598 in the wild and no public exploit code.

Affected product: Yokogawa Electric Corporation FAST/TOOLS. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-66598/ (Markdown: https://insights.sbomify.com/CVE-2025-66598/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-66598
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-66598
- OSV: https://osv.dev/vulnerability/CVE-2025-66598

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-66598/
Summaries are generated and may contain mistakes; the official description above is the record.