CVE-2025-15556Known exploitationNetwork attack vector

Code execution via unverified updater installer

Published Feb 3, 2026 · Updated Feb 3, 2026

Update integrity failure in the WinGUp updater for Notepad++ before 8.8.9 allows remote attackers to execute code through redirected traffic. WinGUp accepts attacker-controlled update metadata and launches the referenced installer without validating its certificate or cryptographic signature. Exploitation requires control of update routing or traffic and an update check; code then runs with the privileges of the Notepad++ user.

CVSS severity7.7
High
EPSS probability1.71%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Update integrity failure in the WinGUp updater for Notepad++ before 8.8.9 allows remote attackers to execute code through redirected traffic. WinGUp accepts attacker-controlled update metadata and launches the referenced installer without validating its certificate or cryptographic signature. Exploitation requires control of update routing or traffic and an update check; code then runs with the privileges of the Notepad++ user.

The record

CVE
CVE-2025-15556
Published
Feb 3, 2026
Updated
Feb 3, 2026
Vendor
Notepad++
Product
Notepad++
Classifications
CWE-494, T1195.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <8.8.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Notepad++ · Notepad++version=0 <8.8.9

Published CVSS scores

7.7VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-494Download of Code Without Integrity Check
T1195.002Compromise Software Supply Chain

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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