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


- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Yes, since 12 Feb 2026 (CISA KEV)
- **Fix available:** No
- **Published:** 3 Feb 2026
- **Updated:** 5 Mar 2026
- **Also known as:** GHSA-cqx4-h5ph-3xj9

## What is CVE-2025-15556?

CVE-2025-15556 is a high-severity vulnerability in notepad-plus-plus, published on 3 Feb 2026. 

### 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.

Weakness: CWE-494 (Download of Code Without Integrity Check)

## Which versions are affected by CVE-2025-15556?

It affects 1 product.


Products: Notepad-Plus-Plus Notepad\+\+.

## How do I fix CVE-2025-15556?

No fix has been published for CVE-2025-15556 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 5 Mar 2026.

## Is CVE-2025-15556 being exploited?

Yes. Attackers have exploited CVE-2025-15556 in the wild since at least 12 Feb 2026.

Public exploit code:

- IoCs and detection rules for the Notepad++ supply chain attack (CVE-2025-15556) — Lotus Blossom APT, June–December 2025. Includes Falcon LogScale queries, YARA/Sigma rules, and MITRE ATT&CK mapping. (github_poc): https://github.com/renat0z3r0/notepadpp-supply-chain-iocs
- https://github.com/George0Papasotiriou/CVE-2025-15556-Notepad-WinGUp-Updater-RCE (github_poc): https://github.com/George0Papasotiriou/CVE-2025-15556-Notepad-WinGUp-Updater-RCE

## Other vulnerabilities in notepad-plus-plus

- [CVE-2026-48778](https://insights.sbomify.com/CVE-2026-48778/): Notepad++: Arbitrary Code Execution via config.xml commandLineInterpreter (high 7.8)
- [CVE-2026-48800](https://insights.sbomify.com/CVE-2026-48800/): Notepad++: Arbitrary Code Execution via shortcuts.xml UserCommand Injection (high 7.8)
- [CVE-2026-52884](https://insights.sbomify.com/CVE-2026-52884/): Notepad++: CVE-2026-48800 Bypass (high 7.8)
- [CVE-2023-47452](https://insights.sbomify.com/CVE-2023-47452/): Privilege escalation in n/a (high 7.8)
- [CVE-2023-40031](https://insights.sbomify.com/CVE-2023-40031/): Notepad++ vulnerable to heap buffer write overflow in Utf8_16_Read::convert (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-15556 and fix it if it is affected.

What it is: CVE-2025-15556 is a high-severity vulnerability in notepad-plus-plus, published on 3 Feb 2026. 
Exploitation: Yes. Attackers have exploited CVE-2025-15556 in the wild since at least 12 Feb 2026.

Affected product: notepad-plus-plus. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-15556/ (Markdown: https://insights.sbomify.com/CVE-2025-15556/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-15556
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-15556
- OSV: https://osv.dev/vulnerability/CVE-2025-15556

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-15556/
Summaries are generated and may contain mistakes; the official description above is the record.