CyberSecBulletin
CVE-2025-15556Exploited in the wildNVD status: Analyzed

Notepad++ Download of Code Without Integrity Check

Published Updated By the CyberSecBulletin desk

CVE-2025-15556 is a high-severity download of code without integrity check vulnerability in notepad-plus-plus, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 8.8.9 as the first without the flaw, so updating notepad-plus-plus to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on February 12, 2026, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update notepad-plus-plus to 8.8.9 or a later version.
  2. Update Notepad++ to 8.8.9 or a later version.
  3. CISA's 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.
  4. Read the advisory on notepad-plus-plus.org for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  6. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Notepad-plus-plusnotepad-plus-plusbefore 8.8.98.8.9
Notepad-plus-plusNotepad++before 8.8.98.8.9

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.07.7HighCNA (vulncheck.com)
CVSS 3.17.5HighNVD

Official 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Download of Code Without Integrity Check

The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.

How developers prevent this class of flaw

  • Perform proper forward and reverse DNS lookups to detect DNS spoofing.
  • Encrypt the code with a reliable encryption scheme before transmitting.
  • Run your code using the lowest privileges that are required to accomplish the necessary tasks. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

More Download of Code Without Integrity Check vulnerabilities (CWE-494)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  4. Deadline for US federal agencies to remediate, set by CISA.
  5. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in notepad-plus-plus

All notepad-plus-plus vulnerabilities

Recent Download of Code Without Integrity Check vulnerabilities

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