Malicious code in css-anchor-pos-fallback (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 (bd0a6c8e1448ffd9abb3732872ea3d49280a422d49524aaa57d0b89a73812f05) The package advertises itself as a CSS anchor-position polyfill but on require executes an IIFE in thunderboltRegistry.js that runs `id`, `whoami`, `uname -a`, `ifconfig`/`ip addr`, and reads `/etc/hosts`, then POSTs the collected output along with hostname, platform, and Node version via fetch to the hardcoded external endpoint http://dxpoc.gt.tc/callback.php/. The module also exports keys named after Wix thunderbolt internal registries (thunderboltRegistry, siteAssetsRegistry, documentManagementRegistry, editorRegistry, corvidRegistry, etc.) with a bundled manifest referencing a parastorage.com unpkg URL, a shape consistent with dependency-confusion targeting of an internal Wix build pipeline. The advertised polyfill purpose is unrelated to shell execution, host reconnaissance, or outbound beaconing.

Source published

4 Oct 2026 23:13:37 UTC

Source modified

4 Oct 2026 23:30:06 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.