CVE-2026-85279 Notepad++: Stack Buffer Overflow in Plugin Lexer Loading via Unchecked GetLexerCount() Return Value
A malicious plugin can trigger a stack buffer overflow in Notepad++, allowing arbitrary code execution within the application process.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-85279?
CVE-2026-85279 is a high-severity memory corruption vulnerability in notepad-plus-plus, published on 22 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Notepad++ is a free and open-source source code editor. Prior to 8.9.8, Notepad++ contains a stack buffer overflow in PluginsManager::loadPluginFromPath in PowerEditor/src/MISC/PluginsManager/PluginsManager.cpp because the plugin-supplied GetLexerCount() result controls a loop that writes to containers[30] without enforcing NB_MAX_EXTERNAL_LANG. A malicious or compromised plugin that reports more than 30 lexers can write beyond the stack array and corrupt control data, which can permit arbitrary code execution in the Notepad++ process context. This issue is fixed in version 8.9.8.
Weakness: CWE-121
Which versions are affected by CVE-2026-85279?
How do I fix CVE-2026-85279?
No fix has been published for CVE-2026-85279 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-85279 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85279 exists.
Sources
Also known as GHSA-h2wq-6x75-h8q2.