Detections
Analytics

CVE-2025-59718

critical

Description

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.

References

https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/

https://www.theregister.com/2026/01/28/fortinet_forticloud_vuln/

https://www.helpnetsecurity.com/2026/01/28/fortinet-forticloud-sso-zero-day-vulnerability-cve-2026-24858/

https://www.databreachtoday.com/fortinet-locks-down-forticloud-sso-amid-zero-day-attacks-a-30612

https://www.darkreading.com/vulnerabilities-threats/fortinet-new-zero-day-malicious-sso-logins

https://www.cisa.gov/news-events/alerts/2026/01/28/fortinet-releases-guidance-address-ongoing-exploitation-authentication-bypass-vulnerability-cve-2026

https://securityaffairs.com/187426/security/fortinet-patches-actively-exploited-fortios-sso-auth-bypass-cve-2026-24858.html

https://cyberscoop.com/ortinet-zero-day-cve-2026-24858-forticloud-sso-auth-bypass/

https://www.bleepingcomputer.com/news/security/fortinet-blocks-exploited-forticloud-sso-zero-day-until-patch-is-ready/

https://www.securityweek.com/fortinet-confirms-forticloud-sso-exploitation-against-patched-devices/

https://www.bleepingcomputer.com/news/security/fortinet-confirms-critical-forticloud-auth-bypass-not-fully-patched/

https://securityaffairs.com/187250/security/fortinet-warns-of-active-forticloud-sso-bypass-affecting-updated-devices.html

https://www.theregister.com/2026/01/22/fortigate_firewalls_hit_by_silent/

https://www.securityweek.com/new-wave-of-attacks-targeting-fortigate-firewalls/

https://www.fortinet.com/blog/psirt-blogs/analysis-of-sso-abuse-on-fortios

https://www.darkreading.com/cloud-security/fortinet-firewalls-malicious-configuration-changes

https://www.bleepingcomputer.com/news/security/hackers-breach-fortinet-fortigate-devices-steal-firewall-configs/

https://thehackernews.com/2026/01/automated-fortigate-attacks-exploit.html

https://securityaffairs.com/187194/hacking/arctic-wolf-detects-surge-in-automated-fortinet-fortigate-firewall-configuration-attacks.html

https://www.helpnetsecurity.com/2026/01/21/patched-fortigate-compromised-via-cve-2025-59718/

https://www.bleepingcomputer.com/news/security/fortinet-admins-report-patched-fortigate-firewalls-getting-hacked/

https://www.bleepingcomputer.com/news/security/over-10-000-fortinet-firewalls-exposed-to-ongoing-2fa-bypass-attacks/

https://securityaffairs.com/185896/hacking/u-s-cisa-adds-a-flaw-in-watchguard-fireware-os-to-its-known-exploited-vulnerabilities-catalog.html

https://www.bleepingcomputer.com/news/security/over-25-000-forticloud-sso-devices-exposed-to-remote-attacks/

https://thehackernews.com/2025/12/watchguard-warns-of-active-exploitation.html

https://www.helpnetsecurity.com/2025/12/17/fortigate-vulnerability-cve-2025-59718-exploited/

https://securityaffairs.com/185765/security/u-s-cisa-adds-a-flaw-in-multiple-fortinet-products-to-its-known-exploited-vulnerabilities-catalog.html

https://www.securityweek.com/in-the-wild-exploitation-of-fresh-fortinet-flaws-begins/

https://www.bleepingcomputer.com/news/security/hackers-exploit-newly-patched-fortinet-auth-bypass-flaws/

https://thehackernews.com/2025/12/fortinet-fortigate-under-active-attack.html

https://securityaffairs.com/185748/security/hackers-are-exploiting-critical-fortinet-flaws-days-after-patch-release.html

https://www.securityweek.com/fortinet-patches-exploited-forticloud-sso-authentication-bypass/

https://thehackernews.com/2026/01/fortinet-confirms-active-forticloud-sso.html

https://www.securityweek.com/fortinet-patches-critical-authentication-bypass-vulnerabilities/

https://thehackernews.com/2025/12/fortinet-ivanti-and-sap-issue-urgent.html

https://securityaffairs.com/185546/security/fortinet-fixed-two-critical-authentication-bypass-vulnerabilities.html

https://www.theregister.com/2025/12/09/december_2025_patch_tuesday/

https://www.bleepingcomputer.com/news/security/fortinet-warns-of-critical-forticloud-sso-login-auth-bypass-flaws/

https://fortiguard.fortinet.com/psirt/FG-IR-25-647

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718

Details

Source: Mitre, NVD

Published: 2025-12-09

Updated: 2025-12-17

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

EPSS

EPSS: 0.05574

Vulnerability Watch

Tenable Research has classified this CVE under the following Vulnerability Watch classification, which includes active and historical (inactive) classifications. You can learn more about these classifications on our blog.

Vulnerability of Interest