CVE-2025-15556

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.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: HIGH
CVSS score: 7.7 / 10
CVSS vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Effective score: 7.7 / 10 HIGH source: CNA overview
CWE(s): CWE-494
Reserved: 2026-02-02
Published: 2026-02-03 00:50 UTC
Last updated: 2026-03-05 01:29 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2025/15xxx/CVE-2025-15556.json
Linked Threat: CVE-2025-15556 — Notepad++ Notepad++: Notepad++ Download of Code Without Integrity Check Vulnerability

CISA Known Exploited Vulnerabilities CISA KEV

CISA has confirmed in-the-wild exploitation of this CVE. Federal agencies must remediate by the due date below; private orgs should treat it as priority-1.

Vulnerability name: Notepad++ Download of Code Without Integrity Check Vulnerability
Vendor / project: Notepad++
Product: Notepad++
Date added to KEV: 2026-02-12
Remediation due: 2026-03-05
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Ransomware campaign use: Unknown
CISA notes: https://notepad-plus-plus.org/news/clarification-security-incident/ ; https://community.notepad-plus-plus.org/topic/27298/notepad-v8-8-9-vulnerability-fix ; https://nvd.nist.gov/vuln/detail/CVE-2025-15556
CISA listing: www.cisa.gov/known-exploited-vulnerabilities-catalog

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-02-03 01:15:57 UTC
NVD last modified: 2026-02-13 14:03:47 UTC
NVD CVSS v3.1: 7.5 / 10 HIGH source: nvd@nist.gov
NVD CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploitability subscore: 1.6 / 10
Impact subscore: 5.9 / 10
EPSS score: 0.0609 (probability of exploitation in next 30 days)
EPSS percentile: 90.87% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2025-206661
Assigner: VulnCheck
Published: Feb 3, 2026, 12:50:29 AM
Updated: Mar 5, 2026, 1:29:51 AM
EUVD base score (CVSS 4.0): 7.7 / 10
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EUVD-reported EPSS: 6.0900
Vendors: notepad-plus-plus
Products: notepad-plus-plus (0 <8.8.9)
Aliases: GHSA-cqx4-h5ph-3xj9

ENISA 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.

EUVD references (5)

Affected products (1)

Vendor	Product	Versions	Platforms
notepad-plus-plus	notepad-plus-plus	`0` (affected)	—

Affected products — CPE 2.3 (1) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:a:notepad-plus-plus:notepad\+\+:*:*:*:*:*:*:*:*

Vendor references (5)

References embedded in the original CVE record by the assigning CNA.

Web references (9)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

http://cwe.mitre.org/data/definitions/494.html rapid7:cwe.mitre.org
https://attackerkb.com/topics/CVE-2025-15556 rapid7:attackerkb.com
https://community.notepad-plus-plus.org/topic/27298/notepad-v8-8-9-vulnerability-fix rapid7:community.notepad-plus-plus.org
https://euvd.enisa.europa.eu/vulnerability/EUVD-2025-206661 rapid7:euvd.enisa.europa.eu
https://github.com/notepad-plus-plus/notepad-plus-plus/commit/bcf2aa68ef414338d717e20e059459570ed6c5ab rapid7:github.com
https://github.com/notepad-plus-plus/wingup/commit/ce0037549995ed0396cc363544d14b3425614fdb rapid7:github.com
https://notepad-plus-plus.org/news/hijacked-incident-info-update/ rapid7:notepad-plus-plus.org
https://www.cve.org/CVERecord?id=CVE-2025-15556 rapid7:www.cve.org
https://www.vulncheck.com/advisories/notepad-plus-plus-wingup-updater-lacks-update-integrity-verification rapid7:www.vulncheck.com

NVD-tagged references (7)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://community.notepad-plus-plus.org/topic/27298/notepad-v8-8-9-vulnerability-fix disclosure@vulncheck.com Release Notes
https://github.com/notepad-plus-plus/notepad-plus-plus/commit/bcf2aa68ef414338d717e20e059459570ed6c5ab disclosure@vulncheck.com Patch
https://github.com/notepad-plus-plus/wingup/commit/ce0037549995ed0396cc363544d14b3425614fdb disclosure@vulncheck.com Patch
https://notepad-plus-plus.org//news//clarification-security-incident/ 134c704f-9b21-4f2e-91b3-4a467353bcc0 Vendor Advisory
https://notepad-plus-plus.org/news/hijacked-incident-info-update/ disclosure@vulncheck.com PatchVendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-15556 134c704f-9b21-4f2e-91b3-4a467353bcc0 US Government Resource
https://www.vulncheck.com/advisories/notepad-plus-plus-wingup-updater-lacks-update-integrity-verification disclosure@vulncheck.com Third Party Advisory

Indicators (2)

IOCs linked to the auto-promoted Threat row.

Type	Value	VirusTotal	Attached
cwe	`CWE-494`	no local data	2026-05-14 02:58 UTC
cve	`CVE-2025-15556`	no local data	2026-05-14 02:58 UTC

Remediations (9)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2025-15556 - Tenable

web:www.tenable.com

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 ...

2026-05-14 16:20 UTC
Microsoft Patch Tuesday May 2026 - 120 Vulnerabilities Fixed, Including ...

web:cybersecuritynews.com

Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.

2026-05-14 16:20 UTC
CVE-2025-15556 - Exploits & Severity - Feedly

web:feedly.com

CVE-2025-15556 is a critical supply chain attack affecting Notepad++, where the vulnerability arises not from the software itself but from a compromised hosting provider's infrastructure that redirected users to malicious mirrors.

2026-05-14 16:20 UTC
Nvd - Cve-2025-15556

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-14 16:20 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-05-14 16:20 UTC
CVE-2025-15556 | High Vulnerability in Notepad++

web:www.appsecure.security

CVE-2025-15556 CVE-2025-15556 : High Vulnerability in Notepad++ A high-severity update integrity verification vulnerability exists in Notepad++ versions prior to 8.8.9. This vulnerability could allow attackers to execute arbitrary code. Immediate patching is essential to mitigate risks.

2026-05-14 16:20 UTC
CVE-2025-15556 - Vulnerability Details - OpenCVE

web:app.opencve.io

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 ...

2026-05-14 16:20 UTC
Dangerous Fake Microsoft Windows Update Confirmed—Do Not Download

web:www.forbes.com

As security researchers warn about a dangerous Microsoft Windows update that isn't legitimate, users must pay close attention to what they are actually downloading.

2026-05-14 16:20 UTC
CISA Required Action

CISA KEV

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Due date: 2026-03-05 Known ransomware campaign use: Unknown

2026-05-14 01:13 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2025-15556.json.

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