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CVE-2025-15556

Notepad++ Download of Code Without Integrity Check

7.5 HIGHActively exploited (CISA KEV)EPSS 1.77%
  1. Published3 Feb 2026
  2. Added to CISA KEV12 Feb 2026
  3. Remediation due5 Mar 2026
Actively exploited (CISA KEV)

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.

Added to KEV: 12 Feb 2026Federal remediation due: 5 Mar 2026

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityHigh
Privileges requiredNone
User interactionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

Notepad-plus-plus Notepad++< 8.8.9

Remediation

Fixed in
Notepad-plus-plus Notepad++≥ 8.8.9

References

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Frequently asked

Is CVE-2025-15556 being actively exploited?

Yes. CVE-2025-15556 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 12 Feb 2026.

How severe is CVE-2025-15556?

CVE-2025-15556 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 1.77% probability of exploitation.

Which products are affected by CVE-2025-15556?

Affected products include Notepad-plus-plus Notepad++.

How do I fix CVE-2025-15556?

Upgrade affected software to a fixed version, for example Notepad-plus-plus Notepad++ 8.8.9 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-15556 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.