CVE-2025-59718: Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
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.
Description quoted from the CVE record (assigned by fortinet, published 2025-12-09).
Weakness: Improper access control
How it can be exploited
Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.
- On CISA KEV since
- 2025-12-16
- US federal deadline
- 2025-12-23
- Ransomware use
- Not known
Public exploit evidence (Exploit Observer)
Also known as: BDU:2025-15540, CNNVD-202512-1217, EUVD-2025-202198, GHSA-fjj2-p33c-f8qq
VEDAS cluster: VEDAS:GAUNTLETBRAND
Exploit Observer links 3 pieces of public exploit code or detection modules that name this CVE or one of its aliases.
Exploit code and modules (3)
Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.
- Code repository: https://github.com/ashwesker/blackash-cve-2025-59718
- Code repository: https://github.com/exfil0/cve-2025-59718-poc
- Code repository: https://github.com/moften/cve-2025-59718-fortinet-poc
Research and write-ups (2)
- Research or write-up: https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719
- Research or write-up: https://www.picussecurity.com/resource/blog/cve-2025-59718-critical-forticloud-sso-authentication-bypass
Vulnerability databases and vendor advisories (6)
Catalogue entries, not exploit evidence.
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2025-202198
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-fjj2-p33c-f8qq
- Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2025-59718
- Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718
- Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202512-1217
- Vulnerability database or vendor advisory: https://www.tenable.com/cve/CVE-2025-59718
News (1)
54 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.
VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.
Live scores
- EPSS
- 0.683
very likely to be attacked soon - VEDAS
- 0.984
strong exploit evidence - On CISA KEV
- Yes, since 2025-12-16
- Detection rule
- None yet
Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish.
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Fortinet FortiSwitchManager | from 7.2.0 up to and including 7.2.6 from 7.0.0 up to and including 7.0.5 | Not stated |
| Fortinet FortiOS | from 7.6.0 up to and including 7.6.3 from 7.4.0 up to and including 7.4.8 from 7.2.0 up to and including 7.2.11 from 7.0.0 up to and including 7.0.17 | Not stated |
| Fortinet FortiProxy | from 7.6.0 up to and including 7.6.3 from 7.4.0 up to and including 7.4.10 from 7.2.0 up to and including 7.2.14 from 7.0.0 up to and including 7.0.21 | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
Exploit Observer also maps it to: fortinet fortios, fortinet fortiproxy, fortinet fortiswitchmanager, fortinet_inc. fortios, fortinet_inc. fortiproxy, fortinet_inc. fortiswitchmanager.
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.
Vendor guidance:
- https://fortiguard.fortinet.com/psirt/FG-IR-25-647
- https://docs.fortinet.com/upgrade-tool/fortigate
- https://nvd.nist.gov/vuln/detail/CVE-2025-59718
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Exploits and technical analysis
- https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/ (third-party-advisory)
Government sources
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-59718 (government-resource)
Other references
- https://fortiguard.fortinet.com/psirt/FG-IR-25-647
- https://cert-portal.siemens.com/productcert/html/ssa-864900.html
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.