# Fortinet Multiple Products: Multiple Products Improper Verification of Cryptographic Signature Vulnerability · pwn.watch

> 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. Added to CISA KEV on 2025-12-16.

Page: https://pwn.watch/i/fortinet-multiple-products-cve-2025-59718 · generated 2026-10-22T21:47:37.879Z

## Status
- Severity: critical · status: closed · patch: patched
- Product: Fortinet Multiple Products
- Started: 2025-12-16 · closed: 2025-12-16
- CVEs: CVE-2025-59718
- Affected: See vendor advisory / CISA notes (versions not always listed in KEV feed)
- Fixed in: See vendor advisory linked in sources

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/fortinet-multiple-products-cve-2025-59718/feed.xml
- JSON Feed: https://pwn.watch/i/fortinet-multiple-products-cve-2025-59718/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/fortinet-multiple-products-cve-2025-59718.json
- This file: https://pwn.watch/i/fortinet-multiple-products-cve-2025-59718/llms.txt

## Updates (newest first)
- 2025-12-16: CISA added CVE-2025-59718 to the KEV catalog (due 2025-12-23).

## Fix brief
# Security brief: Fortinet Multiple Products: Multiple Products Improper Verification of Cryptographic Signature Vulnerability

Source: https://pwn.watch/i/fortinet-multiple-products-cve-2025-59718 · status: closed (closed Dec 16, 2025) · severity: critical · updated Dec 16, 2025

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
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. Added to CISA KEV on 2025-12-16.

Severity detail: CVSS 9.1 (CNA, v3.1); actively exploited (CISA KEV)

- Product: Fortinet Multiple Products
- CVE / advisory ids: CVE-2025-59718

## Affected versions
- See vendor advisory / CISA notes (versions not always listed in KEV feed)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- See vendor advisory linked in sources

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Dec 16, 2025: CISA added CVE-2025-59718 to the KEV catalog (due 2025-12-23).

## Advisories
- [Fortinet advisory: Fortinet Multiple Products](https://fortiguard.fortinet.com/psirt/FG-IR-25-647) (Fortinet)
- [Fortinet advisory: Fortinet Multiple Products](https://docs.fortinet.com/upgrade-tool/fortigate) (Fortinet)
- [NVD: CVE-2025-59718](https://nvd.nist.gov/vuln/detail/CVE-2025-59718) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Caveats
Derived from CISA KEV JSON feed catalogVersion 2026.10.21. CVSS from the CVE record (cvelistV5). Exact affected/fixed version strings are not always in the KEV record; verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier; many entries are older CVEs newly confirmed as exploited in 2025).

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Machine-readable: https://pwn.watch/i/fortinet-multiple-products-cve-2025-59718.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.