CVE-2026-6539 — MEDIUM (4.4)

Vulnerability 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.

CVSS Score

4.4

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

LOW

Integrity

NONE

Availability

LOW

Affected Products

Vendor	Product	Versions
Notepad-Plus-Plus	Notepad\+\+	8.9.3

Related Weaknesses (CWE)

CWE-134

References

https://notepad-plus-plus.org/news/v894-released/Release Notes
https://www.vulncheck.com/advisories/notepad-format-string-injection-via-nativelThird Party Advisory

FAQ

What is CVE-2026-6539?

CVE-2026-6539 is a vulnerability with a CVSS score of 4.4 (MEDIUM). 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 n...

How severe is CVE-2026-6539?

CVE-2026-6539 has been rated MEDIUM with a CVSS base score of 4.4/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-6539?

Check the references section above for vendor advisories and patch information. Affected products include: Notepad-Plus-Plus Notepad\+\+.