CVE-2025-15556: Notepad++ Download of Code Without Integrity Check Vulnerability

High severity, CVSS 7.5. Actively exploited: in CISA KEV since 2026-02-12. EPSS: 1.8% chance of exploitation in the next 30 days.

Notepad++ versions prior to 8.8.9, when using the WinGUp updater, contain an update integrity verification vulnerability where downloaded update metadata and installers are not cryptographically verified. An attacker able to intercept or redirect update traffic can cause the updater to download and execute an attacker-controlled installer, resulting in arbitrary code execution with the privileges of the user.

Affected products

• Notepad-Plus-Plus Notepad++: before 8.8.9 (fixed in 8.8.9)

Published 2026-02-03. Last modified 2026-06-17.