dbcve.org
ForticlientApplication · Fortinet

CVE-2023-41840

HIGH · 7.8 CVSS v3.1 Published 2023-11-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
81/100
Remediation priority · High
No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A untrusted search path vulnerability in Fortinet FortiClientWindows 7.0.9 allows an attacker to perform a DLL Hijack attack via a malicious OpenSSL engine library in the search path.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

FortiClientWindows 7.0.9 contains an untrusted search path vulnerability allowing DLL hijacking. An attacker can place a malicious OpenSSL engine library in the search path, causing the application to load the attacker-controlled DLL instead of the legitimate one, potentially leading to arbitrary code execution.

MitigationApply vendor patches from Fortinet for FortiClientWindows. As a temporary workaround, ensure the application directory and search path are not writable by unprivileged users and avoid placing untrusted DLLs in locations searched by the application.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ForticlientApplication
Affected:= 7.0.9= 7.2.0= 7.2.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed FortiClient version
    Open Windows Settings > Apps > Apps & features, locate FortiClient, and note the version number. Alternatively, open FortiClient and go to Help > About, or run 'fcwin.exe -v' from the FortiClient installation directory.
    Affected if The version displayed is 7.0.9, 7.2.0, or 7.2.1 exactly.
  2. Locate FortiClient installation directory
    The default installation path is C:\Program Files\Fortinet\FortiClient\. Check for the presence of this folder and note its full path.
    Affected if FortiClient is installed and the directory exists.
  3. Check directory permissions for write access
    Right-click the FortiClient installation folder, select Properties > Security, and review Write permissions for Users or non-admin groups. Use icacls command: icacls 'C:\Program Files\Fortinet\FortiClient\'
    Affected if Non-privileged users have Write or Create files permissions to the FortiClient directory.
  4. Inspect for suspicious OpenSSL engine DLLs
    Search the FortiClient installation directory and system PATH directories for .dll files matching OpenSSL engine naming patterns (e.g., *engine*.dll, *.dll in subfolders named 'engines' or 'ssl'). Look for unknown or recently created DLLs.
    Affected if Unexpected DLL files are found in the FortiClient directory or search path that were not part of a legitimate installation.
  5. Review DLL search order behavior
    FortiClient may load OpenSSL engine DLLs from its working directory or paths in the system PATH. Check if the application directory or any directory in PATH is writable by low-privilege users.
    Affected if Writable directories exist in the locations FortiClient searches for DLLs.

You are affected if FortiClient version 7.0.9, 7.2.0, or 7.2.1 is installed AND non-privileged users can write to directories in the DLL search path, allowing placement of malicious OpenSSL engine libraries.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor patches from Fortinet for FortiClientWindows. As a temporary workaround, ensure the application directory and search path are not writable by unprivileged users and avoid placing untrusted DLLs in locations searched by the application.

Recommended fix Moderate confidence

FortiClient 7.0.10 or 7.2.2 (or latest stable version)

  1. Upgrade FortiClient Windows to version 7.0.10 or later, or 7.2.2 or later
  2. Download the updated version from the official Fortinet support portal at https://support.fortinet.com/
  3. Verify the upgrade by checking Help > About FortiClient to confirm the installed version
  4. Ensure the upgrade is tested in a non-production environment before deploying widely
Caveat Standard FortiClient upgrade - review release notes for any endpoint policy or VPN configuration changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Forticlient Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,790
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,864.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-41840 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-41840 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data