CVE-2025-15556: Notepad++ Download of Code Without Integrity Check Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 9 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 1.8%
EPSS score, percentile 78.1 of all scored records
- How severe?
- 7.7 High
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline . Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Which versions are affected?
Affected
- before 8.8.9
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date for this action: .
Advisories and patches
Linked from CISA's catalog entry
- 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
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 8.8.9 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2025-15556 to its Known Exploited Vulnerabilities (KEV) catalog on 12 Feb 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 5 Mar 2026.
- The CVE record was published on 3 Feb 2026, 9 days before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 7.7 (High), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 1.8% (percentile 78.1), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
Notepad++ < 8.8.9 WinGUp Updater Lacks Update Integrity Verification
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-494: Download of Code Without Integrity Check
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |