Threat database

MobaXterm Personal Edition (Portable) 26.4 GA extracts the CygUtils64.plugin file without first verifying its integrity. A local attacker with write permissions on this file can replace the ‘bin/cygwin1.dll’ library contained within it with a malicious library. When the victim opens a Local Shell session or uses a Cygwin-based function, the application extracts the component and loads the tampered library, executing code with the victim’s permissions. Exploitation requires write access to the plugin and does not, in itself, involve privilege escalation.

MobaXterm Personal Edition (Portable), in its 26.3 version (Build 5154), allows arbitrary code execution by loading a malicious DLL located in the same directory as the portable executable. Because the application automatically loads the winspool.drv library from that location during startup, an attacker with local access can place a specially crafted DLL alongside the executable to be executed when the victim launches the application.

MobaXterm Personal Edition (Portable), in its 26.3 version (Build 5154), allows arbitrary code execution by loading malicious DLLs from a temporary directory that is predictable and can be modified by the user. During startup, the application searches for specific DLLs in this location before resorting to the system’s secure paths, enabling an attacker with local access to place a specially crafted DLL to be executed automatically when the victim launches the application.

CVE-2026-6421 is a high-severity vulnerability in Mobatek MobaXterm Home Edition versions up to 26.1 involving an uncontrolled search path in the msimg32.dll library. The vulnerability requires local access and has a high attack complexity, making exploitation difficult. The vendor has released version 26.2 which mitigates this issue. Users are advised to upgrade to this fixed version to address the vulnerability.

MobaXterm versions prior to 26.1 contain an uncontrolled search path element vulnerability. The application calls WinExec to execute Notepad++ without a fully qualified executable path when opening remote files. An attacker can exploit the search path behavior by placing a malicious executable earlier in the search order, resulting in arbitrary code execution in the context of the affected user.