Vulnerability in Notepad++
CVE-2026-6539
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L.
EPSS exploit prediction
EPSS: 0.002 (8.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Notepad++ — versions 0
- Notepad-Plus-Plus Notepad\+\+ — versions 8.9.3
Weakness classification (CWE)
References
- notepad-plus-plus.org/news/v894-released/ (Release Notes, patch)
- www.vulncheck.com/advisories/notepad-format-string-injection-via-nativelang-xml (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-6539?
- CVE-2026-6539 is a medium-severity vulnerability in Notepad++, classified under Use of Externally-Controlled Format String. CVSS score: 4.4/10. Published 2026-04-30.
- How severe is CVE-2026-6539?
- Medium severity. CVSS v3 base score is 4.4 out of 10.