Buffer overflow in Notepad-Plus-Plus
CVE-2026-86054
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.
Vulnerability class: Buffer Overflow
Published .
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.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Notepad-Plus-Plus — versions < 8.9.8
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-86054?
- CVE-2026-86054 is a high-severity vulnerability in Notepad-Plus-Plus, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-09-22.
- How severe is CVE-2026-86054?
- High severity. CVSS v3 base score is 7.8 out of 10.