Cyber Resilience

CVE-2025-15556

Notepad-Plus-Plus Notepad\+\+ ≤ 8.8.9

CISA KEVActive ExploitationEUVD ExploitedPublic PoC
Published
03 February 2026
Modified
13 February 2026
KEV Added
12 February 2026
Patch / advisory
View advisory
CVSS Score v4 7.7
Click a component to see what it means
Raw 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
EPSS Score 0.013 67th percentile
Risk Priority 100 floored blend · peak EPSS

Summary

CVE-2025-15556 is a high-severity Download of Code Without Integrity Check (CWE-494) vulnerability in Notepad-Plus-Plus Notepad\+\+. Its CVSS base score is 7.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); ranked in the top 33% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to CM-14 (Signed Components) and SI-7 (Software, Firmware, and Information Integrity) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-15556 is an update integrity verification vulnerability affecting Notepad++ versions prior to 8.8.9 when using the WinGUp updater. The flaw, classified under CWE-494 (Download of Code Without Integrity Check), arises because downloaded update metadata and installers lack cryptographic verification. This was published on 2026-02-03 with a CVSS v3.1 base score of 7.5 (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H).

An attacker capable of intercepting or redirecting network traffic to the update servers can exploit this during an update check. A victim user must trigger the updater and approve the process (user interaction required), at which point the updater downloads and executes a malicious installer controlled by the attacker. This leads to arbitrary code execution with the privileges of the logged-in user.

Notepad++ advisories and patches recommend updating to version 8.8.9, which addresses the issue through commits in the Notepad++ and WinGUp repositories adding cryptographic verification for updates. Vendor announcements detail the fix and provide incident information related to a hijacked update event.

Vulncheck and community discussions confirm the vulnerability's resolution in the patched release, emphasizing the importance of verifying update integrity in auto-updaters.

OWASP Top 10 for Web (2025)

A08:2025 Software or Data Integrity Failures

EU & UK References

Vulnerability Data

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…

more

download and execute an attacker-controlled installer, resulting in arbitrary code execution with the privileges of the user.

CWE(s)
CWE-494
KEV Date Added
12 February 2026

Related Threats

MITRE ATT&CK Enterprise Techniques

T1195 Supply Chain Compromise Initial Access
Adversaries may manipulate products or product delivery mechanisms prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1072 Software Deployment Tools Execution
Adversaries may gain access to and use centralized software suites installed within an enterprise to execute commands and move laterally through the network.
attack.mitre.org →
T1195.001 Compromise Software Dependencies and Development Tools Initial Access
Adversaries may manipulate software dependencies and development tools prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1195.002 Compromise Software Supply Chain Initial Access
Adversaries may manipulate application software prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-40036Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-40031Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-48800Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-25926Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-6539Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-47452Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2023-40166Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-52885Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-48778Same product: Notepad-Plus-Plus Notepad\+\+
CVE-2026-5525Same product: Notepad-Plus-Plus Notepad\+\+

Affected Assets

notepad-plus-plus
notepad\+\+
≤ 8.8.9

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 9 hardening rules · 5 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

CM-14 Signed Components good match

Requires digital signature verification before component installation, directly stopping execution of code downloaded without integrity checks.

SI-7 Software, Firmware, and Information Integrity good match

Employs integrity verification tools that can identify missing or failed checks on downloaded software after the fact.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-09 full match
prevents

Directly requires assessing authenticity/integrity of software before acquisition and use, preventing unverified downloads.

PR.DS-02 mostly match
prevents

Requires cryptographic integrity protections (signatures/hashes) for data-in-transit, covering downloaded code.

PR.PS-05 mostly match
prevents

Prevents execution of unauthorized software, blocking the outcome of an unchecked download.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.21 Managing information security in the ICT supply chain partial match
prevents

Mandating integrity checks, digital signatures, and origin tracing for ICT components directly reduces the chance that code or firmware lacking an integrity check will be accepted into the organisation’s environment.

A.8.8 Management of technical vulnerabilities none match
none

Requiring suppliers to disclose vulnerabilities and mandating verified updates lowers the chance that code lacking integrity checks will be deployed.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-494
Oracle Linux 9 (1 rule)
  • V-271524 OL 9 must check the GPG signature of software packages originating from external software repositories before installation. prevents CWE-494
RHEL 7 (2 rules)
  • V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-494
  • V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-494
RHEL 8 (1 rule)
  • V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-494
RHEL 9 (1 rule)
  • V-257820 RHEL 9 must check the GPG signature of software packages originating from external software repositories before installation. prevents CWE-494

References