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Malicious code in ts-poly-utls (npm)

0
Critical
Published: 08/05/2026 (08/05/2026, 13:33:47 UTC)
Source: GCVE Database
Product: ts-poly-utls

Description

The npm package ts-poly-utls version 1.2.4 contains malicious code executed during installation. Its postinstall script downloads and runs unverified code from a third-party Vercel deployment controlled by an attacker. The package identity is inconsistent with its documentation, misleading users. Installing this package results in execution of attacker-controlled code on the installer's machine.

Affected software

npmghsa
ts-poly-utls
Affected versions
=1.2.4

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 08/05/2026, 16:50:58 UTC

Technical Analysis

The ts-poly-utls npm package (version 1.2.4) includes a postinstall script (scripts/install-check.cjs) that fetches a remote payload from an untrusted URL (https://polymarket-clob-service.vercel.app/config/clob-math.json). This script downloads a .tgz archive to a temporary directory, extracts it, runs npm install inside the extracted directory, then requires and executes a function (syncSession) from the downloaded code. The remote payload is not pinned by hash or signature, allowing arbitrary code execution. The package's published name does not match its README or homepage, which point to the attacker's Vercel deployment rather than the legitimate Polymarket site. This results in execution of attacker-controlled code on the machine installing the package.

Potential Impact

Installing [email protected] leads to execution of arbitrary attacker-controlled code on the installer's system due to the unverified remote payload fetched and executed during the postinstall phase. This can compromise the system integrity and confidentiality of the affected environment.

Mitigation Recommendations

No official patch or remediation is currently documented. Users should avoid installing ts-poly-utls version 1.2.4. Verify package authenticity before installation and prefer packages from trusted sources. Monitor vendor advisories for updates or official fixes. Since no patch is confirmed, do not install or use this package version.

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Technical Details

Gcve Source
db.gcve.eu
Osv Id
MAL-2026-12811
Osv Schema Version
1.7.4
Ecosystems
["npm"]

Threat ID: 6a73573dbf8831d5391534dd

Added to database: 08/05/2026, 15:31:09 UTC

Last enriched: 08/05/2026, 16:50:58 UTC

Last updated: 09/07/2026, 22:22:13 UTC

Views: 19

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