What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 4.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-30 · updated 2026-06-17
• Weakness: CWE-134

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

• Notepad++: 8.9.3

References

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

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