Malicious code in homestack-cheer (npm)

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (f475cd8b8a3e1dd4563ca0b20d85fde83576ed78c27eb91ca1cd77fbebe0d142) The package is published as homestack-cheer with description 'JS lib support cheerleading', but the README and the UMD build (dist/my-lib.umd.js) present it as a trivial hello-world 'greet' library. The ESM entrypoint declared in package.json 'module' (src/index.js) and src/env_load.js each end with `new Function(atob('<~180KB base64>')).call(this)`, decoding an obfuscated second-stage payload via a runtime string-shuffle routine. When a downstream project bundles this package with webpack/rollup, the ESM path is resolved and the hidden payload is embedded into the resulting application bundle and executed in end-users' browsers. The decoded payload checks `window.location` for the substring 'checkout' and, when a Stripe payment element iframe (#stripe-payment-element iframe) is present, hides the real Stripe iframe, clears the disabled state on the place-order button, and injects a look-alike iframe with id `__privateStripeFrame84331` to intercept card input. The divergence between the benign `main` (UMD greet) and the malicious `module` (ESM Function(atob(...))) constitutes deliberate dual-entrypoint smuggling designed to evade casual review of the package's headline file. ## Source: ghsa-malware (b0622f60729e4dec05a0c9f802b4728a7c579d968532a87d664b759da856ad27) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Source published

21 Sep 2026 03:31:35 UTC

Source modified

1 Oct 2026 23:30:05 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.