Notepad++: Stack Buffer Overflow in expandNppEnvironmentStrs
CVE-2026-54758 is fixed in Notepad++ on 1 platform by Notepad++ 8.9.7 (version 8.9.7), released July 14, 2026. It is not reported as exploited. Patch Radar priority: High.
Notepad++ is a free and open-source source code editor. Prior to 8.9.7, the expandNppEnvironmentStrs function in PowerEditor/src/WinControls/StaticDialog/RunDlg/RunDlg.cpp copies a Notepad++ variable name between $( and ) into the fixed-size wchar_t str[MAX_PATH] stack buffer without bounding the m loop index, allowing a name of 260 or more characters to corrupt adjacent stack data, terminate the process through __report_gsfailure, and potentially execute code. This issue is fixed in version 8.9.7.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Notepad++ | 8.9.7 | Notepad++ 8.9.7 | Jul 14, 2026 |
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