Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Notepad Plus Plus | — | Upgrade NotepadPlusPlus to the latest version | Sep 23, 2026 | Sep 22, 2026 |
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