Threats / Fortinet / CVE-2025-59718
CVE-2025-59718
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Fortinet Multiple Products vulnerability
Fortinet products contain improper cryptographic signature verification in SAML authentication, allowing unauthenticated attackers to bypass FortiCloud SSO login via crafted messages.
Verdict
Today item — known-exploited.
An unauthenticated remote attacker can forge SAML authentication tokens to bypass FortiCloud single sign-on protections across multiple Fortinet products. Active exploitation has been observed in the wild.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
17 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-12-16).
Probability (EPSS)
EPSS 0.63476 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Fortinet, Multiple Products. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-347 CWE-347 — weakness family: Cryptography.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious SAML assertion with an invalid or forged cryptographic signature.
Business
Fortinet's authentication infrastructure fails to properly validate the signature, creating a direct path to unauthorized access.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I submit the forged SAML message to the FortiCloud SSO endpoint without valid credentials.
Business
The authentication system accepts the message due to signature verification bypass, granting me session access.
3
Lateral reach — past segmentation narrative 3
Attacker
I gain unauthenticated access to protected Fortinet management interfaces and cloud services.
Business
Attackers obtain administrative or user-level access to security appliances, enabling lateral movement and data exfiltration across the organization.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05