CVERadar
CRITICAL · CVSS 3.1 9.8CISA KEV · added 2025-12-16EPSS 68.29% (p99)Threat level 84

CVE-2025-59718: Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability

Fortinet · Multiple Products · NVD published 2025-12-10 · posted 2025-12-16 · last modified 2026-06-17

What it is

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.

WeaknessCWE-347
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (source: [email protected])
CISA due date2025-12-23 (for US federal agencies under BOD; a good deadline for everyone)
ATT&CK tacticsDefense Impairment

Exploitation evidence

First exploit evidence seen: 2025-12-16 (earliest date across the sources below).

Exploited in the wild

  • CISA KEV: listed since 2025-12-16. Source

Public exploit code

GitHub proof-of-concept repositories below quality bar

2 public repositories from 2 accounts, first seen 2025-12-17.

Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.

Sources: CISA KEV · nomi-sec/PoC-in-GitHub.

Defend the Chain

The attack chain for CVE-2025-59718 laid across the MITRE ATT&CK Enterprise tactics. Solid cards come from the MITRE CTID KEV mappings; dashed cards are inferred by CVERadar from the CWE or description. Correct defences are real ATT&CK mitigations for that technique.

Threat level 84/100
Defender level 1 · 0 XP
Chain links broken: 0/1

Reconnaissance

Resource Development

Initial Access

Execution

Persistence

Privilege Escalation

Stealth

Defense Impairment

Credential Access

Discovery

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Pick a red technique card on the board, then choose the defence that stops it.

Defend against T1553 Subvert Trust Controls Inferred

Inferred from CWE CWE-347

How to fix it

CISA 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. (source: CISA KEV)

Fixed versions

  • fortinet fortiproxy: upgrade to 7.0.22 or later (affected from 7.0.0)
  • fortinet fortiproxy: upgrade to 7.2.15 or later (affected from 7.2.0)
  • fortinet fortiproxy: upgrade to 7.4.11 or later (affected from 7.4.0)
  • fortinet fortiproxy: upgrade to 7.6.4 or later (affected from 7.6.0)
  • fortinet fortiswitchmanager: upgrade to 7.0.6 or later (affected from 7.0.0)
  • fortinet fortiswitchmanager: upgrade to 7.2.7 or later (affected from 7.2.0)
  • fortinet fortios: upgrade to 7.0.18 or later (affected from 7.0.0)
  • fortinet fortios: upgrade to 7.2.12 or later (affected from 7.2.0)
  • fortinet fortios: upgrade to 7.4.9 or later (affected from 7.4.0)
  • fortinet fortios: upgrade to 7.6.4 or later (affected from 7.6.0)

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

MITRE ATT&CK mitigations for this chain

  • M1038 Execution Prevention (for T1553) : System settings can prevent applications from running that haven't been downloaded through the Apple Store (or other legitimate repositories) which can help mitigate some of these issues. Also enable application control solutions such as AppLocker and/or Device Guard to block the loading of malicious content.
  • M1028 Operating System Configuration (for T1553) : Windows Group Policy can be used to manage root certificates and the <code>Flags</code> value of <code>HKLM\\SOFTWARE\\Policies\\Microsoft\\SystemCertificates\\Root\\ProtectedRoots</code> can be set to 1 to prevent non-administrator users from making further root installations into their own HKCU certificate store.
  • M1026 Privileged Account Management (for T1553) : Manage the creation, modification, use, and permissions associated to privileged accounts, including SYSTEM and root.
  • M1024 Restrict Registry Permissions (for T1553) : Ensure proper permissions are set for Registry hives to prevent users from modifying keys related to SIP and trust provider components. Components may still be able to be hijacked to suitable functions already present on disk if malicious modifications to Registry keys are not prevented.
  • M1054 Software Configuration (for T1553) : HTTP Public Key Pinning (HPKP) is one method to mitigate potential [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557) situations where and adversary uses a mis-issued or fraudulent certificate to intercept encrypted communications by enforcing use of an expected certificate.

Detection Generic guidance

    Response checklist Generic guidance

    1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
    2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
    3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
    4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.

    Sources