Buffer overflow in Notepad-Plus-Plus
CVE-2026-54758
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.
Vulnerability class: Buffer Overflow
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Notepad-plus-plus — versions < 8.9.7
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_CONFIRM)
Frequently asked questions
- What is CVE-2026-54758?
- CVE-2026-54758 is a high-severity vulnerability in Notepad-Plus-Plus, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-08-17.
- How severe is CVE-2026-54758?
- High severity. CVSS v3 base score is 7.8 out of 10.