postcss-minify-selector-parser
This report shows the evidence for postcss-minify-selector-parser@2.0.1. 9 of 9 known versions are blocked or flagged. See all versions.
OpenSSF/OSV Malicious Advisory
imported 4mo ago · by OpenSSF/OSVOpenSSF/OSV advisory MAL-2026-5737 confirms this npm version as malicious.
Advisory
MAL-2026-5737
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in postcss-minify-selector-parser (npm)
Details
The package name impersonates the widely-used postcss-selector-parser library (which it also declares as a dependency and re-exports verbatim from src/selector-parser.js, providing cover for installers who mistype the real package). On top of that legitimate re-export, the package ships a sealed AES-GCM ciphertext as DEFAULT_FINAL_ENCODED_TEXT in src/config/defaults.js together with a hardcoded passphrase (`default-dev-passphrase`) and salt. src/pipeline/custom-codec-pipeline.js line 53 decrypts the blob and evaluates the cleartext via `new Function("require", runnable)(require)`, handing the decrypted code full `require` capability on the installer's machine. This decode-and-eval path is reachable through the package's exported `run` / `decodeAndRunPlain` / `runDefaultDecodedFunction` API, through `require('postcss-minify-selector-parser/cjs-runner')`, and through the bundled `runtime/lib.min.js` and `scripts/cjs-runner.js`. The README documents none of this — it presents the package as a CSS selector parser. The combination of typosquat name, hidden encrypted payload, multi-layer custom codec pipeline (position-unit-codec + encode-decode-codec + AES-GCM) used solely to wrap that payload, and direct `new Function(require)` execution of the decrypted bytes is the canonical opaque-blob-eval supply-chain attack shape. Author field is empty, no repository URL is declared, license is generic ISC.
## Source: ghsa-malware (34994969794d47c784e679fd2f442e839336789f6eacec233553ee18c462e024) 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 & flagged code
0 flagged · loading sourceNo flagged code excerpts are attached to this scan.
Findings
1 High
HighOsv Malicious Advisory
Affected versions and remediation
This report applies to postcss-minify-selector-parser@2.0.1.
The same advisory and Firewall decision cover 9 recorded versions
1.0.11, 1.0.12, 1.0.13, 1.0.14, 1.0.15, 1.0.16, 1.0.17, 1.0.18, 2.0.1
The versions list below shows the verdict for each recorded version.
- Avoid installing postcss-minify-selector-parser@2.0.1. Remove it from direct dependencies and check your lockfile for transitive copies.
- Choose an independently verified alternative or release. This report does not establish that other versions are safe.
- If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.
Evidence last updated: .
Source advisory published: .
This report uses published external intelligence. The advisory does not provide a separate source-code analysis for each listed version.
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