Fortinet FortiClient: Origin validation error allows unauthorized code execution
Summary
An origin validation error (CWE-346) in the local API of FortiClient for macOS and Windows, and FortiClientWindowsPAM, may allow an unauthenticated remote attacker to execute unauthorized code or commands. Exploitation requires that a victim interacts with the attacker's content, for example by opening a crafted link or page. The CVE record gives a CVSS 9.6 score, while the FortiGuard page lists 9.1; the vendor advisory is the reference for the rating.
Affected
- FortiClientMac 7.4.0 through 7.4.7
- FortiClientWindows 7.4.0 through 7.4.7
- FortiClientWindows 7.2.0 through 7.2.14
- FortiClientWindowsPAM 7.4.7 and 7.2.14
- FortiClient 8.0 is not affected according to the vendor.
Fixed in
- FortiClientMac: upgrade to 7.4.8 or above (or 8.0.0 or above)
- FortiClientWindows: upgrade to 7.4.8 or above, or 7.2.15 or above (or 8.0.0 or above)
- FortiClientWindowsPAM: upgrade to 7.4.8 or above, or 7.2.15 or above (or 8.0.0 or above)
Workaround
Unknown.
Exploitation
- Exploited in the wild: Unknown.
- Public proof of concept: Unknown.
- Known exploited status: not listed on the vendor page at the time of research.
Our recommendation
- Inventory all FortiClient for macOS, FortiClient for Windows and FortiClientWindowsPAM installations and record the exact versions.
- Prioritise endpoints in the affected ranges and upgrade to the fixed versions listed above.
- Until patched, instruct users not to open unexpected links or content, and monitor for unusual FortiClient activity.
- Check the FortiGuard advisory and CISA KEV for updates.
Public exploits
Links to third-party sites, not checked by us – exploit code can contain malware. Only use it in isolated test environments.
- Proof of concept on GitHub (5 repositories)
ashrafzaryouh/CVE-2026-121529 · googlesky/CVE-2026-121529 · googlesky/Fortinet2Shell · Ghost-Bx1/cve-2026-121529-forticlient-cors-rce · tc4dy/CVE-2026-121529-Toolkit
Research sources
- FortiGuard PSIRT FG-IR-26-194 fortiguard.fortinet.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 10 Nov 2026, 21:21.
Original description (NVD)
A origin validation error vulnerability in Fortinet FortiClientMac 7.4.0 through 7.4.7, FortiClientWindows 7.4.0 through 7.4.7, FortiClientWindows 7.2.0 through 7.2.14, FortiClientWindowsPAM 7.4.7, FortiClientWindowsPAM 7.2.14 may allow an unauthorized remote attacker to execute unauthorized code or commands. Successful exploitation requires interaction with the victim.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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