CVE-2026-6539

Notepad++ 8.9.3 Format String Injection via nativeLang.xml

MEDIUM
4.4
CVSS Score
Published: April 30, 2026 at 08:31 PM UTC
Updated: June 17, 2026 at 11:00 AM UTC
2 products affected across 2 vendorsNotepad++Notepad Plus Plus

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Severity
MEDIUM4.4
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 8.9.4
Affected range stops below 8.9.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.4MEDIUMVulnCheck
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-134

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