Notepad++: Null pointer dereference in NPPM_SAVESESSION message handler causes crash (DoS)
CVE-2026-86056 is fixed in Notepad++ on 1 platform by Notepad++ 8.9.8 (version 8.9.8), released August 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Notepad++ | 8.9.8 | Notepad++ 8.9.8 | Aug 23, 2026 |
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