CVE-2026-44278 Overview
CVE-2026-44278 is a hard-coded cryptographic key vulnerability [CWE-321] affecting Fortinet FortiClientWindows. The flaw exists in FortiClientWindows versions 7.4.0 through 7.4.2 and all versions of FortiClientWindows 7.2. A local authenticated attacker can leverage the embedded key to decrypt protected data, resulting in information disclosure. The vulnerability carries a CVSS v3.1 score of 5.5 (MEDIUM) and requires local access with low privileges. Fortinet published the advisory under tracking identifier FG-IR-26-129.
Critical Impact
Local attackers with low privileges can recover sensitive information protected by the hard-coded key, breaching confidentiality of FortiClient-managed data on Windows endpoints.
Affected Products
- Fortinet FortiClientWindows 7.4.0 through 7.4.2
- Fortinet FortiClientWindows 7.2 (all versions)
- Windows endpoints running vulnerable FortiClient builds
Discovery Timeline
- 2026-05-12 - CVE-2026-44278 published to NVD
- 2026-05-16 - Last updated in NVD database
Technical Details for CVE-2026-44278
Vulnerability Analysis
The vulnerability stems from the use of a hard-coded cryptographic key embedded in the FortiClientWindows binary. Hard-coded keys [CWE-321] violate the principle that cryptographic material must be unique per installation and stored securely. Any attacker who extracts the key from the binary can decrypt data protected by it across every affected installation.
The CVSS vector indicates the attack requires local access (AV:L) with low privileges (PR:L) and no user interaction. The impact is limited to confidentiality (C:H), with no effect on integrity or availability. This profile aligns with a local information disclosure scenario where a low-privileged user reads or decrypts protected configuration, credentials, or cached data on the host.
Root Cause
The root cause is a static cryptographic key compiled into the FortiClient Windows application. Because every deployed copy of the affected versions shares the same key, extracting the key from one binary compromises the protection of data on all other installations. This eliminates the cryptographic boundary that the algorithm would otherwise provide.
Attack Vector
An attacker with local low-privileged access to a Windows endpoint running an affected FortiClient version can recover the hard-coded key through static analysis of the binary or by inspecting process memory. With the key in hand, the attacker decrypts protected artifacts stored locally by FortiClient. No user interaction is required, and remote exploitation is not possible without prior local access.
No public proof-of-concept code is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The current EPSS probability is 0.011%, indicating low likelihood of exploitation in the wild at this time.
Detection Methods for CVE-2026-44278
Indicators of Compromise
- Presence of FortiClientWindows binary versions 7.4.0, 7.4.1, 7.4.2, or any 7.2.x release on managed endpoints.
- Unexpected access to FortiClient configuration files or registry locations by non-FortiClient processes.
- Local user-mode tools performing memory inspection against FortiClient.exe or related service processes.
Detection Strategies
- Inventory installed FortiClient versions across the fleet using endpoint management or software inventory tools.
- Monitor for process access events targeting FortiClient binaries and data directories by unauthorized processes.
- Audit local file reads against FortiClient configuration directories under %ProgramData%\Fortinet and user profile paths.
Monitoring Recommendations
- Enable command-line and process creation logging on Windows endpoints to identify reverse engineering or memory dumping tools.
- Forward FortiClient and Windows Security event logs to a centralized SIEM for correlation and retention.
- Alert on unexpected handle opens to FortiClient processes by non-administrative or non-trusted binaries.
How to Mitigate CVE-2026-44278
Immediate Actions Required
- Identify all Windows endpoints running FortiClientWindows 7.2.x or 7.4.0 through 7.4.2 and prioritize them for upgrade.
- Review the Fortinet Security Advisory FG-IR-26-129 for the vendor's recommended fixed version.
- Restrict local administrative and interactive access on endpoints handling sensitive FortiClient configurations.
Patch Information
Fortinet has published advisory FG-IR-26-129 documenting the vulnerability and remediation guidance. Administrators should consult the Fortinet PSIRT advisory for the patched FortiClientWindows release and upgrade affected systems to a non-vulnerable version.
Workarounds
- Limit local logon rights on endpoints running FortiClient to reduce the population of users able to extract the key.
- Apply application control policies that block unauthorized debugging, memory inspection, and reverse engineering tools.
- Rotate any credentials or secrets that may have been stored or protected by FortiClient on affected versions after patching.
# Configuration example: enumerate FortiClient versions on Windows hosts via PowerShell
Get-CimInstance -ClassName Win32_Product |
Where-Object { $_.Name -like 'FortiClient*' } |
Select-Object Name, Version, InstallDate
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
