CVE-2025-59718criticalunder attackCWE-347

CVE-2025-59718: critical vulnerability in Fortinet FortiOS

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90Vexday Risk Score

Prioritize patching. It under exploitation confirmed by CISA, has an official Brazilian government alert and has a public proof of concept.

ssvc Actcvss 9.1epss 68%
from disclosure to weapon8 days
Published on NVDDec 9
1st PoC+8d
CISA KEV+7d
Official alert in Brazil

Brazil's federal government published an alert, recommendation or bulletin that cites this vulnerability.

  • CTIR Gov · RECOMENDAÇÃO 12/2026 · 24 Jun 2026Recomendação Técnica: Campanha FortiBleed – Exposição de Credenciais e Comprometimento de Dispositivos Fortinet FortiGateread on gov.br ↗
  • CTIR Gov · ALERTA 50/2026 · 15 Jun 2026Vulnerabilidades em dispositivos Fortinet associadas ao FortiBleedread on gov.br ↗
  • CISC Gov.br · 23 Jan 2026Exploração Ativa de Bypass de Autenticação em Dispositivos Fortinet (Patch Bypass)read on gov.br ↗
Source: CTIR Gov (GSI) and CISC Gov.br, under the CC BY-ND 3.0 license.
Action required by CISAfederal deadline: 2025-12-23

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

In short

Fortinet products fail to properly verify digital signatures in SAML login messages, allowing attackers to bypass FortiCloud single sign-on authentication without valid credentials. This is critical because it grants unauthorized access to protected systems.

Technical detail

CWE-347 vulnerability in SAML response signature validation across multiple Fortinet products (FortiOS, FortiProxy, FortiSwitchManager). An unauthenticated attacker can craft a malicious SAML response to forge authentication tokens and gain unauthorized access to FortiCloud SSO-protected resources, with no pre-authentication required.

Summary generated and translated by AI from the official description.

The full analysis of this CVE is available in Portuguese →

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.
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
Affected products
Fortinet · FortiOSFortinet · FortiProxyFortinet · FortiSwitchManager
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