CVE-2025-15556
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.
do firstApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? No. The attack involves intercepting or redirecting update traffic, which is not an HTTP request but network-level manipulation. Such attacks cannot be reliably detected or blocked by a web application firewall.
Also consider: patch
Based on an AI reading of the CVE description, and no vendor rule found yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2025-15556 being exploited?
Yes. CVE-2025-15556 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2025-15556?
CVE-2025-15556 is rated High with a CVSS score of 7.5. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2025-15556?
Yes. A fix has been recorded for CVE-2025-15556. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2025-15556 affect?
CVE-2025-15556 affects notepad-plus-plus:notepad\+\+. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
- affected< 8.8.9
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
public exploits
Unvetted proof-of-concept code on GitHub: 2 GitHub proofs of concept
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
cisa ssvc
- exploitation
- active
- automatable
- no
- technical impact
- total
Assessed by CISA 13 Feb 2026 (SSVC 2.0.3).
timeline
- 3 Feb 2026Published
- 9 Feb 2026First proof-of-concept repository on GitHub (unvetted) · 6 days later
- 12 Feb 2026Added to CISA KEV (exploited in the wild) · 3 days later
- 13 Feb 2026CISA SSVC assessment: exploitation active · 1 day later
- 5 Mar 2026CISA remediation due date (US federal agencies) · 20 days later
- 5 Mar 2026CVE record last updated · same day later
- 2 Nov 2026Analysed by vulneraibility.com · 243 days (about 8 months) later
- Advisorynotepad-plus-plus.org /news/hijacked-incident-info-update/
- Advisoryvulncheck.com /advisories/notepad-plus-plus-wingup-updater-lacks-update-integrity-verification
- Advisorynotepad-plus-plus.org //news//clarification-security-incident/
- Patchcommunity.notepad-plus-plus.org /topic/27298/notepad-v8-8-9-vulnerability-fix
- Patchgithub.com /notepad-plus-plus/notepad-plus-plus/commit/bcf2aa68ef414338d717e20e059459570ed6
- Patchgithub.com /notepad-plus-plus/wingup/commit/ce0037549995ed0396cc363544d14b3425614fdb
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-15556
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.