CVE-2025-59718 — Fortinet Fortiproxy
CISA KEVAs of 2025-12-17, CVE-2025-59718 is a CRITICAL-severity vulnerability in Fortinet Fortiproxy, CVSS v3.1 9.8, EPSS 7.6% (91.8th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-12-16), with a US federal remediation deadline of 2025-12-23. Threadlinqs Intelligence links 3 tracked threat campaigns to CVE-2025-59718, most recently “Edge Infrastructure Under Siege: Tenable and SentinelOne Datasets Reveal Convergent Nation-State and Criminal Exploitation of Perimeter Devices”.
Last updated: 2025-12-17
What is CVE-2025-59718?
A improper verification of cryptographic signature vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0 through 7.2.11, FortiOS 7.0.0 through 7.0.17, FortiProxy 7.6.0 through 7.6.3, FortiProxy 7.4.0 through 7.4.10, FortiProxy 7.2.0 through 7.2.14, FortiProxy 7.0.0 through 7.0.21, FortiSwitchManager 7.2.0 through 7.2.6, FortiSwitchManager 7.0.0 through 7.0.5 allows an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML response message.
The record classifies CVE-2025-59718 under weakness class CWE-347. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 3 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 277 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 7.6% probability of exploitation in the next 30 days, higher than 91.8% of all scored CVEs
- CISA KEV
- Listed since 2025-12-16, federal remediation deadline 2025-12-23
- Threadlinqs priority
- 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- Published
- 2025-12-09, last modified 2025-12-17
Is CVE-2025-59718 being exploited?
CISA added CVE-2025-59718 to the Known Exploited Vulnerabilities catalog on 2025-12-16, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2025-12-23 under BOD 22-01. It currently carries a trending score of 38 in the Threadlinqs vulnerability feed.
Affected products and versions
- Fortinet: Fortiproxy, Fortiswitchmanager, Fortios
How to fix CVE-2025-59718
The record marks a vendor fix as available for CVE-2025-59718. Patch reference: https://fortiguard.fortinet.com/psirt/FG-IR-25-573. Vendor advisory: https://fortiguard.fortinet.com/psirt/FG-IR-25-647. Because CVE-2025-59718 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2025-12-23. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2025-59718
3 tracked threats in the Threadlinqs corpus reference CVE-2025-59718, either in the campaign’s CVE list or as an indicator on the campaign record.
- Edge Infrastructure Under Siege: Tenable and SentinelOne Datasets Reveal Convergent Nation-State and Criminal Exploitation of Perimeter Devices — HIGH · 2026-08-26
- FortiBleed: Mass Credential Compromise Campaign Against Internet-Exposed Fortinet FortiGate Devices (86,644 Devices, 194 Countries) — CRITICAL · 2026-07-11
- FortiGate SSO Authentication Bypass Campaign (CVE-2025-59718, CVE-2025-59719, CVE-2026-24858) — CRITICAL · 2026-03-10
Sources
Seeded from nvd and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.
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