CISA Warns of Notepad++ Code Execution Vulnerability Exploited in Attacks

CVE-2025-15556 is a critical Notepad++ WinGUp updater flaw that fails to verify integrity of downloaded update packages, enabling attackers who can intercept or redirect update traffic to install and execute arbitrary code on Windows endpoints; CISA added the issue to its Known Exploited Vulnerabilities catalog, vendors released a patch (Notepad++ 8.8.9+), and organizations are urged to patch, disable WinGUp, scan for outdated installs, and apply network mitigations.