CVE-2026-86054

HIGH 7.8

Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path

CVSS Score

7.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-121
Vendor	notepad-plus-plus
Product	notepad-plus-plus
Published	Sep 22, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

notepad-plus-plus / notepad-plus-plus

< 8.9.8

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx github.com: https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf github.com: https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8 notepad-plus-plus.org: https://notepad-plus-plus.org/news/v898-released