CVE-2026-54758Notepad++: Stack Buffer Overflow in expandNppEnvironmentStrs

Description

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-gv94-327x-2gc5
• https://github.com/notepad-plus-plus/notepad-plus-plus/commit/0a9527e9f7140a2323e25d14e362b46ee0efc3db
• https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.7