notepad-plus-plus Notepad++ up to 8.9.6 RunDlg RunDlg.cpp expandNppEnvironmentStrs stack-based overflow

Summaryinfo

A vulnerability was found in notepad-plus-plus Notepad++ up to 8.9.6. It has been classified as problematic. Affected by this issue is the function expandNppEnvironmentStrs of the file PowerEditor/src/WinControls/StaticDialog/RunDlg/RunDlg.cpp of the component RunDlg. The manipulation leads to stack-based overflow. This vulnerability is listed as CVE-2026-54758. The attack must be carried out locally. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in notepad-plus-plus Notepad++ up to 8.9.6. This issue affects the function expandNppEnvironmentStrs of the file PowerEditor/src/WinControls/StaticDialog/RunDlg/RunDlg.cpp of the component RunDlg. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-54758 since 06/16/2026. The exploitation is known to be easy. Attacking locally is a requirement. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 8.9.7 eliminates this vulnerability.

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Productinfo

Type

• Document Reader Software

Vendor

• notepad-plus-plus

Name

• Notepad++

Version

• 8.9.0
• 8.9.1
• 8.9.2
• 8.9.3
• 8.9.4
• 8.9.5
• 8.9.6

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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