CVERadar
HIGH · CVSS 4.0 7.7CISA KEV · added 2026-02-12EPSS 1.77% (p78)Threat level 54

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

Notepad++ · Notepad++ · NVD published 2026-02-03 · posted 2026-02-12 · last modified 2026-06-17

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.

WeaknessCWE-494
CVSS vectorCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (source: [email protected])
CISA due date2026-03-05 (for US federal agencies under BOD; a good deadline for everyone)
ATT&CK tacticsn/a

Exploitation evidence

First exploit evidence seen: 2026-02-12 (earliest date across the sources below).

Exploited in the wild

  • CISA KEV: listed since 2026-02-12. Source

Public exploit code

GitHub proof-of-concept repositories below quality bar

2 public repositories from 2 accounts, first seen 2026-02-09.

Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.

Sources: CISA KEV · nomi-sec/PoC-in-GitHub.

No ATT&CK techniques could be mapped or inferred for this CVE yet.

How to fix it

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. (source: CISA KEV)

Fixed versions

  • notepad-plus-plus notepad\+\+: upgrade to 8.8.9 or later

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

Detection Generic guidance

    Response checklist Generic guidance

    1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
    2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
    3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
    4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.

    Sources