Notepad++ DLL Hijacking Vulnerability Let Attackers Execute Malicious Code

A DLL hijacking vulnerability has been identified in Notepad++, a widely used source code editor. This vulnerability, tracked as CVE-2025-56383, could enable attackers to execute arbitrary code on affected systems.

The vulnerability is present in Notepad++ version 8.8.3 and may affect all installed versions. It allows a local attacker to execute code by placing a malicious DLL file in a location where the application will load it. This exploit can compromise application integrity and may be used to maintain persistence or escalate privileges.

DLL hijacking involves manipulating the way Windows applications locate and load necessary libraries. An attacker can replace a legitimate DLL with a malicious one in a directory prioritized in the search order. In Notepad++, the vulnerability can be exploited by replacing a plugin DLL, such as NppExport.dll , with a malicious version.

The attacker can rename the original DLL to ensure the application continues to function while forwarding legitimate function calls to the renamed DLL. This proxying technique allows the malicious payload to execute unnoticed by the user.

A demonstration of the exploit shows that replacing NppExport.dll with a malicious version results in arbitrary code execution when Notepad++.exe is launched. This was confirmed by the appearance of a test message box, indicating the exploit's success.

The primary risk associated with this vulnerability is local code execution. An attacker with initial system access can use this flaw to maintain persistence, as the attacker's code will execute whenever the user opens Notepad++.

There is currently no official patch for CVE-2025-56383 from the Notepad++ developers. Users should ensure their systems are free from prior infections and download Notepad++ only from official sources. System administrators are advised to implement file integrity monitoring to detect unauthorized changes.

Users should remain vigilant for unexpected application behavior until a fix is released.

Based on reporting by Cyber Security News.