Exploited. On CISA's list since 2026-02-12.
Notepad++ Download of Code Without Integrity Check Vulnerability
CVE-2025-15556 · Notepad++ Notepad++ · Published 2026-02-03
How bad would it be?
7.7 out of 10
CVSS rates it high.
How likely is it to be used?
1.8%
Estimated chance of exploitation in the next 30 days, higher than 78% of all scored flaws (EPSS, 2026-10-29).
Is it already being used?
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 239 days ago (2026-03-05).
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Notepad++ when using the WinGUp updater, contains a download of code without integrity check vulnerability that could allow an attacker to intercept or redirect update traffic to download and execute an attacker-controlled installer. This could lead to arbitrary code execution with the privileges of the user.
What the flaw is
Notepad++ versions prior to 8.8.9, when using the WinGUp updater, contain an update integrity verification vulnerability where downloaded update metadata and installers are not cryptographically verified. An attacker able to intercept or redirect update traffic can cause the updater to download and execute an attacker-controlled installer, resulting in arbitrary code execution with the privileges of the user.
From the NVD.
Fixes and advisories
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Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
CWE-494 · CISA KEV; NVD record: disclosure@vulncheck.com. We have not selected a close learning match for this label.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
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Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.