CVE-2025-56383
📋 TL;DR
CVE-2025-56383 is a DLL hijacking vulnerability in Notepad++ v8.8.3 that allows attackers to replace legitimate DLL files with malicious ones, potentially executing arbitrary code. This vulnerability primarily affects users who install Notepad++ in directories with weak permissions. The vulnerability is disputed because exploitation requires non-standard installation conditions.
💻 Affected Systems
- Notepad++
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the Notepad++ user, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Limited impact due to the requirement of specific installation conditions; most users with default installations or proper directory permissions are unaffected.
If Mitigated
Minimal to no impact if Notepad++ is installed in protected directories with proper access controls and user permissions.
🎯 Exploit Status
Exploitation requires write access to the installation directory, which typically means the attacker already has some level of access to the system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not applicable - vulnerability disputed by vendor
Vendor Advisory: https://github.com/notepad-plus-plus/notepad-plus-plus
Restart Required: No
Instructions:
No official patch. Consider updating to latest version and ensure proper installation directory permissions.
🔧 Temporary Workarounds
Secure Installation Directory
windowsReinstall Notepad++ in a protected directory like Program Files with proper NTFS permissions
Uninstall Notepad++
Reinstall to C:\Program Files\Notepad++ (default location)
Restrict Directory Permissions
windowsModify NTFS permissions on Notepad++ installation directory to restrict write access
icacls "C:\Path\To\Notepad++" /inheritance:r
icacls "C:\Path\To\Notepad++" /grant:r "SYSTEM:(OI)(CI)F"
icacls "C:\Path\To\Notepad++" /grant:r "Administrators:(OI)(CI)F"
icacls "C:\Path\To\Notepad++" /grant:r "Users:(OI)(CI)RX"
🧯 If You Can't Patch
- Install Notepad++ in default Program Files directory with proper permissions
- Use application whitelisting to prevent execution of unauthorized DLLs in Notepad++ directory
🔍 How to Verify
Check if Vulnerable:
Check if Notepad++ is installed in a directory where unprivileged users have write/modify permissionsCheck Version:
Open Notepad++ → Help → About Notepad++Verify Fix Applied:
Verify installation directory permissions restrict write access to non-admin users📡 Detection & Monitoring
Log Indicators:
- Unexpected DLL loads from Notepad++ process
- File creation/modification events in Notepad++ installation directory by non-admin users
Network Indicators:
- Not typically network exploitable
SIEM Query:
EventID=4663 OR EventID=4656 AND ObjectName LIKE '%Notepad++%' AND SubjectUserName NOT IN ('SYSTEM', 'Administrators')🔗 References
- https://github.com/notepad-plus-plus/notepad-plus-plus
- https://github.com/zer0t0/CVE-2025-56383-Proof-of-Concept
- https://github.com/zer0t0/CVE-2025-56383-Proof-of-Concept/issues/1
- https://www.vicarius.io/vsociety/posts/cve-2025-56383-detect-notepad-vulnerability
- https://www.vicarius.io/vsociety/posts/cve-2025-56383-mitigate-notepad-vulnerability
