Vulnerability · Published Apr 30, 2026 · Assigned by VulnCheck

CVE-2026-6539Notepad++ 8.9.3 Format String Injection via nativeLang.xml

Medium 4.4

In plain English

A medium-severity security flaw in Notepad++ from Notepad++. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).

Severity (CVSS 3.1)4.4Medium

Exploit odds (30 days)0.2%top 91.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
Notepad++	Notepad++	0 – before 8.9.4

Weakness: CWE-134 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

References

https://notepad-plus-plus.org/news/v894-released/ patch
https://www.vulncheck.com/advisories/notepad-format-string-injection-via-nativelang-xml third-party-advisory