Vulnerability
CVE-2025-59718
Fortinet FortiOS, FortiProxy and FortiSwitchManager: improper verification of cryptographic signature
Most severe levelDEFCON 3 · Substantial risk
Official data
- CVSS 3.1
- 9.1 · critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C - Weakness
- CWE-347
- EPSS
- 68.29% probability of exploitation in the next 30 days, higher than 99% of CVEs
- CISA KEV catalogue
- Yes, since 16 December 2025
Sources: NVD (CVSS, weakness, publication), FIRST (EPSS), CISA (KEV catalogue).
Data read on 4 November 2026.
Timeline
- 9 December 2025Published on NVD
- 16 December 2025Added to the CISA KEV catalogue
- 17 December 2025First in the DefenceLevel briefing
In DefenceLevel briefings4 days
- 22 January 2026Worth watching
- 19 December 2025Still ongoingDEFCON 4
- 18 December 2025Still ongoingDEFCON 4
- 17 December 2025New in the last 24 hoursDEFCON 3
Last 12 months.
The full analysis is in the briefingThe full analysis is in your archive
Why it matters now, who is affected and what to do: every day at 05:00 UTC, for subscribers.Why it matters, who is affected and what to do, as in the daily briefing.
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