Executive brief
Notepad++, a widely used text and source code editor, contains a security flaw in its automatic update mechanism. An attacker who can intercept a user's internet traffic could trick the application into downloading and installing malicious software instead of a legitimate update. This could allow an attacker to take full control of the user's computer, and there are reports that this vulnerability has been exploited in the wild.
Technical details
Notepad++ versions prior to 8.8.9 utilize the WinGUp updater, which fails to perform cryptographic integrity verification on downloaded update metadata and installer binaries (CWE-494). An attacker positioned to perform a Man-in-the-Middle (MitM) attack or DNS redirection can intercept the update request and serve a malicious payload. Because the updater does not validate digital signatures or hashes, it will execute the attacker-controlled installer with the privileges of the local user. This vulnerability has been added to the CISA Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation. Users should update to version 8.8.9 or later to remediate the issue.
Affected products
- Notepad++ Notepad++ Prior to 8.8.9
Timeline
- 2026-02-02: disclosed: Initial disclosure by VulnCheck
- 2026-02-12: kev added: Added to CISA Known Exploited Vulnerabilities catalog
- 2026-02-12: advisory: NVD publication date