Malicious code in css-env-function-shim (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 (03e6fced50259d6d3781ef3917caba965e4744420188c3e06919541b64e2e294) Package self-describes as a CSS env() shim but ships thunderboltRegistry.js, which runs an IIFE at module load that base64-decodes the strings 'child_process' and 'execSync', dynamically requires child_process, and shells out whoami, uname, cat /etc/hosts, ifconfig/ip addr, id, and hostname. The collected output is POSTed to a hardcoded webhook.site URL (webhook.site/0492a36c-4d7b-408a-865c-226db25987ba) and beaconed to a subdomain of davdpb8lhot13kgmnhp0863x9g83mpswq.oast.live for DNS exfiltration. All sensitive identifiers (module name, method name, commands, destination host, UUID path, OAST subdomain) are stored as base64 blobs or String.fromCharCode arrays and reconstructed at runtime to defeat static inspection. index.js is a stub; the module factory is re-exported under nine Wix-internal registry key names (thunderboltRegistry, siteAssetsRegistry, editorRegistry, corvidRegistry, and similar), and the shipped registry-manifest.min.json aliases numerous Wix thunderbolt *Registry.js URLs on parastorage.com to this package's thunderboltRegistry.js — a dependency-confusion lure targeting Wix's internal build so that any importer of those names triggers the exfiltration IIFE at require time.

Source published

4 Oct 2026 23:13:53 UTC

Source modified

4 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

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