Vulnerability · Published Aug 17, 2026 · Assigned by GitHub_M

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

High 7.8

In plain English

A high-severity stack buffer overflow in notepad-plus-plus from notepad-plus-plus. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).

Severity (CVSS 3.1)7.8High

Exploit odds (30 days)0.2%top 90.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
notepad-plus-plus	notepad-plus-plus	< 8.9.7

Weakness: CWE-121, CWE-787 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

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