Notepad++ 8.9.3 Format String Injection via nativeLang.xml
CVE-2026-6539 is fixed in Notepad++ on 1 platform by Notepad++ 8.9.4 (version 8.9.4), released April 26, 2026. It is not reported as exploited. Patch Radar priority: Routine.
Notepad++ 8.9.3 contains a format string injection vulnerability in the Find Results panel handler that allows attackers to cause denial of service and information disclosure by crafting a malicious nativeLang.xml language pack file. Attackers can distribute a poisoned language pack through community channels that triggers format string interpretation when a user performs search operations, leading to access violations and potential leakage of stack or register contents.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Notepad++ | 8.9.4 | Notepad++ 8.9.4 | Apr 26, 2026 |
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