What products are affected by CVE-2025-59718?

CVE-2025-59718 affects Fortinet Multiple Products. Refer to the vendor advisory and NVD record for affected versions.

Is there a public exploit for CVE-2025-59718?

Yes. Public exploit code or proof-of-concept has been identified for CVE-2025-59718. This lowers the barrier for exploitation and increases the urgency of patching. Organizations should prioritize remediation immediately.

What is the EPSS score for CVE-2025-59718?

CVE-2025-59718 has an EPSS score of 9.5%, placing it in the 93th percentile. This means it has a 9.5% probability of being exploited in the next 30 days, higher than 93% of all known vulnerabilities. EPSS (Exploit Prediction Scoring System) is maintained by FIRST and uses real-world threat data to estimate exploitation likelihood.

Actively Exploited — CISA KEV

CVE-2025-59718: Fortinet Multiple Products Critical Vulnerability

Severity: Critical | CVSS 3.1: 9.8 | Published: 2025-12-09 | KEV Added: 2025-12-16

What is CVE-2025-59718?

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.

Technical Analysis

Weakness Classification

This vulnerability is classified as CWE-347.

Attack Vector Breakdown

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Impact Analysis

This vulnerability is exploitable over the network, meaning any system reachable via the internet or internal network is potentially at risk without physical access. The attack complexity is low, requires no special privileges, and needs no user interaction — making it straightforward to exploit at scale. Successful exploitation can result in full confidentiality breach (complete data disclosure), complete integrity compromise (data modification or code execution), total availability loss (denial of service).

Exploitation Probability (EPSS): 9.5% chance of exploitation in the next 30 days (93th percentile). While the base probability may appear low, inclusion in CISA KEV confirms real-world exploitation is already occurring.

Exploit Availability

Public exploit code or proof-of-concept is available for CVE-2025-59718. This significantly increases the risk of exploitation, as attackers can use or adapt existing exploit code rather than developing their own. A public exploit reference has been identified. Organizations should treat this as an urgent patching priority.

Is CVE-2025-59718 being exploited?

Yes. CVE-2025-59718 is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, restricted to CVEs with confirmed active exploitation in the wild. CISA added this vulnerability on 2025-12-16. Inclusion in KEV triggers the patching mandate under BOD 22-01 for U.S. federal civilian agencies, with a remediation deadline of 2025-12-23. Additionally, public exploit code is available, which lowers the barrier for attackers.

How to fix CVE-2025-59718

Upgrade FortiOS or the affected product firmware to the fixed version listed in the FortiGuard PSIRT advisory. For FortiGate devices, use the firmware upgrade path tool to determine the correct upgrade sequence. If immediate patching is not possible, apply the recommended workaround (e.g. disabling affected features, restricting management interface access). Check the Fortinet PSIRT Advisories page for the specific patch or update. CISA's Known Exploited Vulnerabilities catalog requires U.S. federal agencies to remediate this vulnerability by the due date shown below under Binding Operational Directive 22-01. Private organizations should treat KEV entries as priority-one patches because active exploitation has been confirmed in the wild.

Related Vulnerabilities

Other actively exploited vulnerabilities affecting Multiple Products or sharing the same weakness (CWE-347):

CVE-2026-24858 (Critical 9.8) [same product] — An Authentication Bypass Using an Alternate Path or Channel vulnerability…
CVE-2025-32756 (Unknown N/A) [same product] — Fortinet FortiFone, FortiVoice, FortiNDR and FortiMail contain a stack-based…
CVE-2025-43510 (High 7.8) [same product] — A memory corruption issue was addressed with improved lock state checking…
CVE-2025-43520 (Medium 5.5) [same product] — A memory corruption issue was addressed with improved memory handling. This…
CVE-2025-31277 (High 8.8) [same product] — The issue was addressed with improved memory handling. This issue is fixed in…

Frequently asked questions

Is CVE-2025-59718 critical?

CVE-2025-59718 has a CVSS 3.1 base score of 9.8 — Critical severity. It should be treated as a priority patch, especially given the active exploitation confirmed by CISA. The availability of public exploit code further increases the urgency.

Is CVE-2025-59718 being actively exploited?

Yes — CISA added CVE-2025-59718 to the Known Exploited Vulnerabilities catalog on 2025-12-16. Inclusion in KEV means CISA has confirmed in-the-wild exploitation. Public exploit code has also been identified, making exploitation accessible to a broader range of threat actors.

How do I patch CVE-2025-59718?

Apply the security update from Fortinet for Multiple Products. Federal agencies must remediate by 2025-12-23 under BOD 22-01. Refer to the Fortinet PSIRT Advisories for the official patch.

What type of vulnerability is CVE-2025-59718?

CVE-2025-59718 is classified under CWE-347.

What is the CVSS score for CVE-2025-59718?

CVE-2025-59718 has a CVSS 3.1 base score of 9.8, classifying it as Critical severity. The attack vector is Network, attack complexity is Low, and no privileges are required.