High severity · published Sep 22, 2026
CVE-2026-86054
Notepad++: Stack Buffer Overflow in `NppParameters::writeSession` via overlong session path
7.8
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 13% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NO
notepad-plus-plus · notepad-plus-plus
< 8.9.8 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-86054
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-86054
x_refsource_CONFIRM
https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-pxgg-96p2-c3hx
x_refsource_MISC
https://github.com/notepad-plus-plus/notepad-plus-plus/commit/046af3f626be7715886412313fc18f58b30dfcaf
x_refsource_MISC
https://github.com/notepad-plus-plus/notepad-plus-plus/releases/tag/v8.9.8
x_refsource_MISC
https://notepad-plus-plus.org/news/v898-released
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