clsx-js
This report shows the evidence for clsx-js@1.0.5. 3 of 3 known versions are blocked or flagged. See all versions.
OpenSSF/OSV Malicious Advisory
imported 4mo ago · by OpenSSF/OSVOpenSSF/OSV advisory MAL-2026-4531 confirms this npm version as malicious.
Advisory
MAL-2026-4531
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in clsx-js (npm)
Details
On `npm install`, dist/postinstall.js base64-decodes the URL https://api.npoint.io/984b75c022a70cf00c39, fetches JSON from this anonymous mutable JSON-hosting service via axios, and pipes the response's `data.content` into a detached `node` child process's stdin for execution. The fetch has no version pin, no hash/signature verification, and the source is operator-mutable — the attacker can swap the executed payload at any time. The package additionally typosquats the widely-used `clsx` utility (by Luke Edwards): name is a one-token edit, and the description, author name, email, and homepage are copied verbatim from the legitimate `clsx` to impersonate the upstream maintainer. The genuine `clsx` ships no postinstall; this fork adds one whose only purpose is the remote-code dropper. A malformed `Dependencies` (capital-D) field also lists `child_process`, a known squat name. Installing this package on any machine results in arbitrary attacker-controlled code execution under the installer's user account.
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 clsx-js@1.0.5.
The same advisory and Firewall decision cover 3 recorded versions
1.0.3, 1.0.4, 1.0.5
The versions list below shows the verdict for each recorded version.
- Avoid installing clsx-js@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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