CVE-2026-54758

High

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.

SeverityHigh
CVSS7.8
Exploit probability—
ProductNotepad-plus-plus
PublishedAug 17, 2026
First seenAug 17, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
notepad-plus-plus notepad-plus-plus< 8.9.7—

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CVE-2026-54758 · Notepad-plus-plus · Dark Radar