CVE-2026-6539 Notepad++ 8.9.3 Format String Injection via nativeLang.xml
Attackers can cause denial of service and information disclosure in Notepad++ by distributing a malicious language pack file.
- 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-2026-6539?
CVE-2026-6539 is a medium-severity vulnerability in Notepad++, published on 30 Apr 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++ 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.
Weakness: CWE-134
Which versions are affected by CVE-2026-6539?
It affects 1 product.
Products include Notepad-Plus-Plus Notepad\+\+.
How do I fix CVE-2026-6539?
No fix has been published for CVE-2026-6539 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-6539 being exploited?
There is no known exploitation of CVE-2026-6539 in the wild and no public exploit code.
Other vulnerabilities in Notepad++
- CVE-2025-15556 Notepad++ Download of Code Without Integrity Check
- CVE-2026-48778 Notepad++: Arbitrary Code Execution via config.xml commandLineInterpreter
- CVE-2026-48800 Notepad++: Arbitrary Code Execution via shortcuts.xml UserCommand Injection
- CVE-2026-52884 Notepad++: CVE-2026-48800 Bypass
- CVE-2023-47452 Privilege escalation in n/a
Sources
Also known as GHSA-vfqp-r766-g759.