CASCACascade Atlas

Evidence dossier

CVE-2025-15556

Notepad++ < 8.8.9 WinGUp Updater Lacks Update Integrity Verification

61.0–76.5Priority evidence range
As known Jul 19, 2026, 5:00 AM UTCgen-56ccdaf9

Normalized restatement

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.

State
PUBLISHED
Published
Feb 3, 2026
Updated
Mar 5, 2026
Evidence coverage
85%
CISA KEVCatalog member

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

FIRST EPSS1.27%

2026-07-18 · v2026.06.15 · percentile 66.5%

Source stateNo scored conflict

Distinct CVSS assessments remain side by side; none are averaged.

Source comparison

Who said what

CISA-ADPindependent enrichment
container

CISA ADP Vulnrichment

VulnCheckoriginal assertion
container

Notepad++ < 8.8.9 WinGUp Updater Lacks Update Integrity Verification

CISA KEVoriginal assertion
observed_exploitation

Notepad++ Download of Code Without Integrity Check Vulnerability

FIRST EPSSoriginal assertion
model_probability

Probability 0.012680000000; percentile 0.665190000000

Applicability

Cited product scope

Trace impact →
notepad-plus-plusnotepad-plus-plus
[{"status": "affected", "version": "0", "lessThan": "8.8.9", "versionType": "semver"}]unknown
Unknown vendorUnknown product
cpe:2.3:a:notepad-plus-plus:notepad\+\+:*:*:*:*:*:*:*:*; end excluding 8.8.9supported

Assessments

CVSS by origin

7.5
nvd@nist.govCVSS 3.1 · role PrimaryCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
7.7
disclosure@vulncheck.comCVSS 4.0 · role SecondaryCVSS: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
7.7
VulnCheckCVSS 4.0 · role unknownCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Limitations and unknowns

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; unresolved scope remains unknown.
  • NVD-carried upstream facts remain derivative and are not independent corroboration.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.