What is CVE-2025-59719?
An improper verification of cryptographic signature vulnerability in Fortinet FortiWeb 8.0.0, FortiWeb 7.6.0 through 7.6.4, FortiWeb 7.4.0 through 7.4.9 may allow an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML response message.
The record classifies CVE-2025-59719 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. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 323 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)
- 29.2% probability of exploitation in the next 30 days, higher than 98.1% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 8.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2025-12-09, last modified 2026-08-11
Is CVE-2025-59719 being exploited?
It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.
Affected products and versions
- Fortinet: Fortiweb, Fortiweb 8.0.0
How to fix CVE-2025-59719
The record marks a vendor fix as available for CVE-2025-59719. Patch reference: https://fortiguard.fortinet.com/psirt/FG-IR-24-535. Vendor advisory: https://fortiguard.fortinet.com/psirt/FG-IR-25-647. 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-2025-59719
7 tracked threats in the Threadlinqs corpus reference CVE-2025-59719, either in the campaign’s CVE list or as an indicator on the campaign record.
- Rapid7 Q3 2026 Threat Landscape: High-Severity Flaws Exploited in 3 Days as The Gentlemen and Qilin Ransomware Dominate — HIGH · 2026-10-21
- PEERSTITCH: Stealthy Memory-Resident FortiGate Implant Deployed via FortiManager CVE-2024-47575 by CL-STA-0954 (UNC5820) — CRITICAL · 2026-10-14
- FortiBleed: Ongoing Credential-Harvesting Campaign Against Fortinet FortiGate Firewalls and SSL VPN Gateways Feeds INC/Lynx and Payload Ransomware Access (FBI/USSS Alert) — HIGH · 2026-10-06
- Multiple Vulnerabilities in Fortigate NGFW on RUGGEDCOM APE1808 Devices (SSA-864900) — Including Actively Exploited FortiCloud SSO Bypass (CVE-2025-59718/-59719) and FortiOS Heap Overflow (CVE-2025-25249) — CRITICAL · 2026-09-13
- 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
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on .