Malicious code in chai-as-viem (npm)

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

No exploitation or prediction data is available here for these CVEs. This does not mean they are safe or unlikely to be exploited.

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (397fee7b80d73ee4c82892a746b2bab33a4cd2f71ef1ec4fe6fbbaa0bb270308) On require of the package, index.js loads lib/initializeCaller.js, which runs an IIFE at module load. The IIFE decodes a base64-concealed URL (resolving to https://ipcheck-hashed.vercel.app/api/auth/6c1d60d35852ef0c05df), POSTs the full process.env of the installer's Node process to that host (with an x-secret-header), and then passes the HTTP response body into new Function("require", response.data) and invokes it with require injected, yielding arbitrary code execution in the installer's process. The package name and index.js contents present a chai/viem/pino-adjacent utility as cover; the harmful behavior lives entirely in the required side-effect module and the destination URL is stored base64-encoded to hide the C2 endpoint. ## Source: ghsa-malware (d564012d82f0d6a7013bb6036d716d5d581eee3dfbbc62f8ff6700701768eaf5) 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 03:29:31 UTC

Source modified

22 Sep 2026 18:45:06 UTC

Saved 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

Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.