CVE-2025-66597
Weak cryptography in FAST/TOOLS may allow TLS traffic decryption.
Is CVE-2025-66597 being exploited?
Not confirmed. CVE-2025-66597 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.17% probability of exploitation in the next 30 days.
How severe is CVE-2025-66597?
CVE-2025-66597 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2025-66597?
Yes. A fix has been recorded for CVE-2025-66597. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2025-66597 affect?
CVE-2025-66597 affects FAST/TOOLS R9.01-R10.04 (Packages: RVSVRN, UNSVRN, HMIWEB, FTEES, HMIMOB). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2025-66597?
Plan upgrade to patched version when available; enforce strong ciphers
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Decrypts TLS/HTTPS traffic to FAST/TOOLS web server; enables eavesdropping and MITM on OT networks.
Monitor only
- affected>= R9.01 and <= R10.04
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.