CVE-2025-56383 identifies a DLL hijacking vulnerability in Notepad++ version 8.8.3. DLL hijacking occurs when an application loads a malicious DLL instead of the legitimate one, allowing an attacker to execute arbitrary code with the privileges of the affected application. In this case, the vulnerability arises if Notepad++ is installed in a directory tree that permits write access to unprivileged users, enabling them to replace or insert a malicious DLL. The vulnerability is classified under CWE-427 (Uncontrolled Search Path Element). The CVSS v3.1 base score is 8.4, indicating high severity, with attack vector local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The vulnerability is disputed because it depends on insecure installation practices rather than a flaw in the software itself. No patches or fixes have been published yet, and no known exploits are reported in the wild. The threat is significant in environments where multiple users share systems or where directory permissions are misconfigured, potentially allowing attackers to escalate privileges or execute malicious code silently.

For European organizations, the impact of CVE-2025-56383 can be substantial, especially in shared workstation environments or development teams where Notepad++ is installed in non-standard directories with lax permissions. Successful exploitation could lead to full system compromise, data theft, or disruption of operations due to arbitrary code execution. This risk is heightened in sectors with sensitive data such as finance, healthcare, and government agencies. The vulnerability undermines confidentiality, integrity, and availability of affected systems. Although exploitation requires local access and write permissions to the installation directory, insider threats or malware that gains limited access could leverage this vulnerability to escalate privileges or persist undetected. The lack of patches means organizations must rely on configuration and access control measures to mitigate risk. The absence of user interaction and authentication requirements makes this vulnerability easier to exploit once the prerequisite conditions are met.

1. Ensure Notepad++ is installed only in directories with strict access controls, preventing write permissions for unprivileged users. 2. Review and harden file system permissions on all systems where Notepad++ is installed, especially in shared or multi-user environments. 3. Use application whitelisting or endpoint protection solutions to detect and block unauthorized DLL modifications or executions. 4. Monitor file integrity of DLLs associated with Notepad++ using file integrity monitoring tools. 5. Educate system administrators and users about the risks of installing software in insecure locations. 6. Consider deploying Notepad++ in a controlled environment or using alternative text editors with less risk exposure until a patch is available. 7. Regularly audit systems for unusual DLL files or unexpected changes in application directories. 8. Implement least privilege principles to limit the number of users who can write to application directories. 9. Stay informed about updates from Notepad++ developers and apply patches promptly once released.