Actively exploited
Listed in CISA’s Known Exploited Vulnerabilities catalog since December 16, 2025.
CVE-2025-59718
Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability
Added to KEV December 16, 2025
Alert details
- Source feed
- CISA KEV
- CVE ID
- CVE-2025-59718
- CWE
- CWE-347
- Affected products
- Multiple Products · Fortinet Multiple Products · Fortinet
What happened
Fortinet FortiOS, FortiSwitchMaster, FortiProxy, and FortiWeb contain an improper verification of cryptographic signature vulnerability that may allow an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML message. Please be aware that CVE-2025-59719 pertains to the same problem and is mentioned in the same vendor advisory. Ensure to apply all patches mentioned in the advisory.
What it means for your business
Fortinet Multiple Products is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2025-59718). Fortinet FortiOS, FortiSwitchMaster, FortiProxy, and FortiWeb contain an improper verification of cryptographic signature vulnerability that may allow an unauthenticated attacker to bypass the FortiCloud SSO login authentication via a crafted SAML message. Please be aware that CVE-2025-59719 pertains to the same problem and is mentioned in the same vendor advisory. Ensure to apply all patches mentioned in the advisory. CISA remediation due date: 2025-12-23. If you need help checking exposure, call (864) 335-9223.
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date: December 23, 2025
Sources
Related briefs
Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability
Fortinet Multiple Products is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2025-25249). Fortinet FortiOS, FortiSwitchManager, and FortiSASE contain a heap-based buffer overflow vulnerability that allows an attacker to execute unauthorized code or commands via specially crafted packets. CISA remediation due date: 2026-09-12. If you need help checking exposure, call (864) 335-9223.
Fortinet FortiMail Path Traversal Vulnerability
Fortinet FortiMail is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-104286). Fortinet FortiMail contains a path traversal and an improper neutralization of NULL byte or NULL character vulnerability that may allow an unauthenticated attacker to write arbitrary files on the underlying system via crafted HTTP or HTTPS requests. CISA remediation due date: 2026-10-04. If you need help checking exposure, call (864) 335-9223.
Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
Citrix NetScaler is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-88779). Citrix NetScaler ADC (formerly Citrix ADC) and Citrix NetScaler Gateway (formerly Citrix Gateway) contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for a denial of service. CISA remediation due date: 2026-10-07. If you need help checking exposure, call (864) 335-9223.
Heap buffer overflow in ANGLE in Microsoft Edge vulnerability
Heap buffer overflow in ANGLE in Microsoft Edge vulnerability (CVE-2025-10502) was added to Microsoft’s security update guidance. Information published. If you need help checking exposure, call (864) 335-9223.
Need help patching?
PremierePC monitors KEV alerts for managed clients and helps teams prioritize remediation before attackers do.