# CVE-2025-59718: Fortinet Multiple Products auth bypass via improper SAML signature verification

Source: https://junglewise.ai/threats/cve-2025-59718-fortinet-multiple-products-auth-bypass-via-improper-saml  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-12-09. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2025-59718 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2025-12-09

A vulnerability exists in several Fortinet networking products, including the FortiOS operating system used in firewalls. This flaw allows an unauthorized person to bypass the login screen and gain administrative access to the device by sending a specially crafted message. If exploited, an attacker could take full control of the network equipment, potentially leading to data theft, network outages, or further attacks on the internal corporate network.

Technologies: [Apple Multiple Products](https://junglewise.ai/threats/technologies/multiple-products), [Fortinet FortiOS](https://junglewise.ai/threats/technologies/fortios), [Fortinet FortiProxy](https://junglewise.ai/threats/technologies/fortiproxy), [Fortinet FortiSwitchManager](https://junglewise.ai/threats/technologies/fortiswitchmanager), [Fortinet FortiWeb](https://junglewise.ai/threats/technologies/fortiweb), [Siemens Ruggedcom Ape1808](https://junglewise.ai/threats/technologies/ruggedcom-ape1808). Vendors: [Apple](https://junglewise.ai/threats/vendors/apple), [Fortinet](https://junglewise.ai/threats/vendors/fortinet), [Siemens](https://junglewise.ai/threats/vendors/siemens).

## Quick answers

**Is CVE-2025-59718 exploited in the wild?** Yes. CVE-2025-59718 is known to be exploited in the wild, first recorded on 16 December 2025. Treat it as urgent.

**How severe is CVE-2025-59718?** Critical severity, with a CVSS score of 9.8, published 9 December 2025.

**Which products and versions are affected?** Fortinet FortiOS 7.6.0 through 7.6.3, 7.4.0 through 7.4.8, 7.2.0 through 7.2.11, 7.0.0 through 7.0.17; Fortinet FortiProxy 7.6.0 through 7.6.3, 7.4.0 through 7.4.10, 7.2.0 through 7.2.14, 7.0.0 through 7.0.21; Fortinet FortiSwitchManager 7.2.0 through 7.2.6, 7.0.0 through 7.0.5; Fortinet FortiWeb 8.0.0, 7.6.0 through 7.6.4, 7.4.0 through 7.4.9; and 1 more.

**Is there a fix for CVE-2025-59718?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2025-59718 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2025-59718?** Check whether you run Apple Multiple Products, Fortinet FortiOS, Fortinet FortiProxy or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability (CWE-347) is caused by the improper verification of cryptographic signatures within the SAML authentication process. An unauthenticated, remote attacker can exploit this by sending a specially crafted SAML response message to the affected device's management interface. If the 'FortiCloud SSO login' feature is enabled (which may occur automatically during FortiCare registration), the attacker can bypass authentication and gain administrative access. The vulnerability has been observed being exploited in the wild. Patches are available in FortiOS 7.6.4, 7.4.9, 7.2.12, and 7.0.18, with similar updates for other affected product lines.

## Affected products

- Fortinet FortiOS 7.6.0 through 7.6.3, 7.4.0 through 7.4.8, 7.2.0 through 7.2.11, 7.0.0 through 7.0.17
- Fortinet FortiProxy 7.6.0 through 7.6.3, 7.4.0 through 7.4.10, 7.2.0 through 7.2.14, 7.0.0 through 7.0.21
- Fortinet FortiSwitchManager 7.2.0 through 7.2.6, 7.0.0 through 7.0.5
- Fortinet FortiWeb 8.0.0, 7.6.0 through 7.6.4, 7.4.0 through 7.4.9
- Siemens RUGGEDCOM APE1808 (Fortinet NGFW) Versions with Fortinet NGFW < V7.4.9 or < V7.6.6

## Timeline

- 2025-12-09: disclosed: Initial publication by Fortinet
- 2025-12-12: exploited: Arctic Wolf observed active exploitation in the wild
- 2025-12-16: kev added: Added to CISA Known Exploited Vulnerabilities catalog

## References

- [https://fortiguard.fortinet.com/psirt/FG-IR-25-647](https://fortiguard.fortinet.com/psirt/FG-IR-25-647)
- [https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/](https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/)
- [https://cert-portal.siemens.com/productcert/html/ssa-864900.html](https://cert-portal.siemens.com/productcert/html/ssa-864900.html)

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