@onereach/postcss-scoped-selectornpm

npm/@onereach/postcss-scoped-selector is affected by the large-scale, self-propagating npm supply-chain worm of 2026-08-04 (the "Shai-Hulud: Here We Go Again" wave) — the same campaign that began with the compromise of the keyv and cacheable maintainer account. The listed version(s) were trojanized and republished by the worm after it reached an npm publish token belonging to a maintainer in this namespace; the payload enumerates every package a stolen token controls and republishes each with the same hook, so many packages under this scope were poisoned in the same short window. Every poisoned release adds a preinstall hook ("preinstall": "node setup.mjs") that runs on a bare npm install, before any project code. setup.mjs downloads a standalone Bun runtime and runs a byte-identical, heavily obfuscated ~728 KB second-stage credential stealer (shipped as Math_Symbol.js / math_init.js). It harvests GitHub, npm, AWS, GCP, Azure, HashiCorp Vault and Kubernetes credentials plus generic secrets and private keys (TruffleHog-style sweep), reads CI/CD secrets and identifies build runners, then republishes further packages the stolen token can reach. Rather than a fixed command-and-control host, it exfiltrates stolen findings to attacker-created GitHub repositories (descriptions reading "Shai-Hulud: Here We Go Again") and over DNS. Treat any environment that installed an affected version (with install scripts enabled) as compromised: rotate and revoke all reachable credentials (npm and GitHub tokens, cloud keys, Vault/Kubernetes secrets, and CI org/repo secrets). Part of the August 2026 npm worm that poisoned 400+ packages across many organizations.

Package advertises itself as a small PostCSS selector-scoping plugin, but its preinstall lifecycle (scripts.preinstall: node setup.mjs) auto-executes on npm install and performs an alternate-runtime dropper flow. setup.mjs is variable-name obfuscated (obfuscator.io-style _0x... identifiers with inline string-lookup tables for URLs and commands); it downloads the Bun runtime archive from a github.com/oven-sh/bun release URL into a temp directory, chmods the binary executable, and invokes execFileSync(bunPath, [path.join(D, 'math_init.js')], {stdio:'inherit'}) to run the sibling file math_init.js under Bun. math_init.js is a ~727KB heavily-obfuscated bundle using a shuffled string-array (n7gIxM=[...]) plus a WV8StW rotation decoder, with no readable source. A PostCSS plugin has no native-build or runtime reason to fetch a second language runtime, and executing an opaque obfuscated payload through that runtime — rather than through Node where standard scanners operate — is an evasion pattern. Installing the package results in execution of attacker-controlled, unreviewable code on the installer's machine with user privileges.

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.