Vulnerability · Published Sep 22, 2026 · Assigned by GitHub_M

CVE-2026-86056Notepad++: Null pointer dereference in NPPM_SAVESESSION message handler causes crash (DoS)

Medium 5.5

In plain English

A medium-severity null pointer dereference in notepad-plus-plus from notepad-plus-plus. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).

Severity (CVSS 3.1)5.5Medium

Exploit odds (30 days)0.2%top 94.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Notepad++ is a free and open-source source code editor. Prior to 8.9.8, the NPPM_SAVESESSION handler in PowerEditor/src/NppBigSwitch.cpp converts lParam to a sessionInfo pointer and dereferences its nbFile, files, and sessionFilePathName members without checking for null. A process running at the same or a higher Windows integrity level on the same desktop can send NPPM_SAVESESSION with a null lParam, immediately terminating Notepad++ and causing denial of service and loss of unsaved documents. This issue is fixed in version 8.9.8.

Affected products (as reported)

Vendor	Product	Versions
notepad-plus-plus	notepad-plus-plus	< 8.9.8

Weakness: CWE-476 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/notepad-plus-plus/notepad-plus-plus/security/advisories/GHSA-j85c-6wc9-p98p x_refsource_CONFIRM
https://github.com/notepad-plus-plus/notepad-plus-plus/commit/8b33f52e7aa488b1222d3cfce5903a38dd63101f 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 x_refsource_MISC