CVE-2025-15556: Notepad++ Notepad++ exploited

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it 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.

Description quoted from the CVE record (assigned by VulnCheck, published 2026-02-03).

Weakness: CWE-494 Download of Code Without Integrity Check

How it can be exploited

Exploitable over the network with high attack complexity with no special attack requirements needing no privileges and a user must take an action. Impact: confidentiality high, integrity high, availability high. 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

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.

On CISA KEV since: 2026-02-12
US federal deadline: 2026-03-05
Ransomware use: Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-15900, CNNVD-202602-526, EUVD-2025-206661, GHSA-cqx4-h5ph-3xj9

VEDAS cluster: VEDAS:BEEBRAVO

Exploit Observer links 1 piece of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (1)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Code repository: https://github.com/george0papasotiriou/cve-2025-15556-notepad-wingup-updater-rce

Vulnerability databases and vendor advisories (5)

Catalogue entries, not exploit evidence.

Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2025-206661
Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-cqx4-h5ph-3xj9
Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2025-15556
Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-15556
Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202602-526

10 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS: 0.017
some chance of attack soon
VEDAS: 0.970
strong exploit evidence
On CISA KEV: Yes, since 2026-02-12
Detection rule: None yet

EPSS (chance of attack)

VEDAS (exploit evidence)

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

Who is affected

Product	Affected	Not affected
notepad-plus-plus notepad-plus-plus	before 8.8.9	Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: don_ho notepad++, notepad-plus-plus notepad\+\+.

How to fix it

Fixed versions stated in the CVE record: 8.8.9.

CISA 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.

Vendor guidance:

How to detect it

There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.

Advisories on this CVE

Notepad++ update infrastructure hijack (CVE-2025-15556), Jun to Dec 2025 (February 2026)

References

Vendor advisories and patches

Exploits and technical analysis

https://www.vulncheck.com/advisories/notepad-plus-plus-wingup-updater-lacks-update-integrity-verification (third-party-advisory)
https://notepad-plus-plus.org//news//clarification-security-incident/ (third-party-advisory)

Government sources

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-15556 (government-resource)

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.

CVE-2025-15556: Notepad++ Download of Code Without Integrity Check Vulnerability