Redazione RHC : 29 September 2025 09:14
A critical DLL hijacking vulnerability has been identified in Notepad++ version 8.8.3 by security researchers, with the flaw assigned CVE-2025-56383.
The vulnerability specifically targets the Notepad++ plugin system, specifically the NppExport.dll file located in the Notepad++pluginsNppExport directory.
This flaw allows attackers to execute arbitrary code by replacing legitimate Dynamic Link Library (DLL) files within the application’s plugin directory with malicious versions that retain the same export functions.
Attackers can exploit this weakness by creating a malicious DLL file with identical export functions that forward calls to the original DLL while simultaneously executing malicious code.
When users launch Notepad++, the application automatically loads these plugin DLLs, creating the opportunity for malicious code execution.
The attack method involves replacing the original DLL file with a counterfeit version that appears legitimate but contains embedded malicious functionality.
Successful exploitation of the vulnerability requires attackers to have access to the local file system and be able to modify files within the Notepad++ installation directory.
While this limits the scope of the attack to scenarios where attackers already have some level of access to the system, it can serve as an effective privilege escalation or persistence mechanism.
The vulnerability was assigned a CVSS 3.1 score of 7.8 (High), indicating significant security implications.
The attack vector is classified as local with low complexity and requires low privileges and user interaction to succeed.
Security researcher zer0t0 has posted a proof-of-concept on GitHub, showing how the vulnerability can be exploited using the NppExport.dll plugin.
The demonstration involves replacing the original DLL with a malicious version called original-NppExport.dll, while keeping the rogue version of NppExport.dll in its place.
While no official patch has been released yet, users should exercise caution when downloading Notepad++ from unofficial sources or allowing untrusted software to modify their system.
Organizations should monitor their Notepad++ installations for unauthorized changes to plugin DLL files.
Since Notepad++ is still widely used in a variety of contexts, fixing this vulnerability is critical for both developers and users.
The vulnerability affects not only version 8.8.3, but potentially also other versions of Notepad++ that use similar plugin loading mechanisms.
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