CVE-2023-41840: Fortinet FortiClientWindows · Escalation of privilege
Affects Fortinet FortiClientWindowsSource CVE Database V5
Not known to be exploited · CVSS 7.4 High.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:XExploitation evidence
Disclosed: evidence found.
CVE published 14 Nov 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Fortinet FortiClientWindows | Affected
| Fixed in– |
AI-suggested
1. Monitor Fortinet’s advisories closely and apply official patches immediately upon release to address CVE-2023-41840. 2. Until patches are available, implement strict DLL search path controls by configuring FortiClientWindows and the operating system to load DLLs only from trusted directories. 3. Employ application whitelisting solutions to prevent unauthorized DLLs from loading. 4. Restrict local user permissions to the minimum necessary to reduce the risk of local privilege escalation. 5. Use endpoint detection and response (EDR) tools to monitor for suspicious DLL loading and anomalous process behavior related to FortiClientWindows. 6. Conduct regular audits of installed software versions across endpoints to identify vulnerable FortiClientWindows installations. 7. Educate IT and security teams about the nature of DLL hijacking attacks and signs of exploitation. 8. Consider network segmentation to limit lateral movement if an endpoint is compromised. 9. Implement robust logging and alerting to detect potential exploitation attempts early.
Description
CVE-2023-41840 is a high-severity vulnerability affecting Fortinet FortiClientWindows versions 7.0.9 and 7.2.0. It arises from an untrusted search path issue that enables a DLL hijacking attack via a malicious OpenSSL engine library placed in the search path. Exploiting this vulnerability allows an attacker with limited privileges to escalate their privileges without requiring user interaction. The vulnerability impacts confidentiality, integrity, and availability of affected systems. No known exploits are currently reported in the wild. European organizations using FortiClientWindows, especially in countries with high Fortinet market penetration and critical infrastructure reliance on Fortinet products, are at risk.