# CVE-2026-86056: 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.

- Web page: https://patchblox.com/security/cve/CVE-2026-86056
- Priority: Routine
- CVSS: 5.5
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 22, 2026
- Weakness: CWE-476: NULL Pointer Dereference
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-86056

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Notepad++ | 8.9.8 | [Notepad++ 8.9.8](https://patchblox.com/security/data/fix/windows-app/notepad-.notepad-8.9.8.md) | Aug 23, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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