---
id: CVE-2026-86054
title: Notepad++ is a free and open-source source code editor
summary: >-
  Notepad++ is a free and open-source source code editor. Prior to 8.9.8,
  Notepad++ contains a stack buffer overflow in NppParameters::writeSession in
  PowerEditor/src/Parameters.cpp because it copies a session path derived from
  -settingsDi…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-121
vendor: notepad-plus-plus
product: notepad-plus-plus
affected:
  - notepad-plus-plus < 8.9.8
published: '2026-09-22'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T18:28:25.093'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86054'
references:
  - url: >-
      https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf
    label: security-advisories@github.com
  - url: 'https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8'
    label: security-advisories@github.com
  - url: >-
      https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx
    label: security-advisories@github.com
  - url: 'https://notepad-plus-plus.org/news/v898-released'
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
epss: 0.00202
epssPercentile: 0.08921
ingestedAt: '2026-09-22T18:08:12.499Z'
---

## Overview

Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in NppParameters::writeSession in PowerEditor/src/Parameters.cpp because it copies a session path derived from -settingsDir= into backupPathName[MAX_PATH] with unbounded wcscpy and appends SESSION_BACKUP_EXT with unbounded wcscat. A sufficiently long settings directory causes the backup suffix to exceed the fixed stack buffer when Notepad++ saves the session, and the protected release build terminates through its stack canary, causing denial of service. This issue is fixed in version 8.9.8.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.