registry / ac-polyfills / 99.9.9

ac-polyfills@99.9.9

OSV Malicious Advisory

imported 20d ago · by OpenSSF/OSV

OpenSSF/OSV advisory MAL-2026-782 confirms this npm version as malicious. ac-polyfills@2.10.0 declares a preinstall lifecycle script in package.json (line 7-8) that runs `wget` to a hardcoded webhook.site collector URL (https://webhook.site/381d4406-8f87-4aab-961f-7a9496c21821/), sending the installer's username ($(whoami)), current working directory ($(pwd)), and hostname ($(hostname)) as query parameters...

Advisory

MAL-2026-782

Source

OpenSSF Malicious Packages via OSV

Summary

Malicious code in ac-polyfills (npm)

Details

ac-polyfills@2.10.0 declares a preinstall lifecycle script in package.json (line 7-8) that runs `wget` to a hardcoded webhook.site collector URL (https://webhook.site/381d4406-8f87-4aab-961f-7a9496c21821/), sending the installer's username ($(whoami)), current working directory ($(pwd)), and hostname ($(hostname)) as query parameters. This fires automatically on `npm install` with no user interaction, exfiltrating installer identity and host information to a third-party webhook collector. The package name and shape are consistent with a dependency-confusion probe targeting an internal package name.

Decision reason

OpenSSF Malicious Packages via OSV confirms ac-polyfills@99.9.9 as malicious (MAL-2026-782): Malicious code in ac-polyfills (npm)

References

OSV advisory PACKAGE

Source & flagged code

0 flagged

No flagged code excerpts are attached to this scan.

Source & flagged code

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Findings

1 High

HighOsv Malicious Advisory

Affected versions and remediation

This report applies to ac-polyfills@99.9.9.

See version security history for other recorded verdicts.

Avoid installing ac-polyfills@99.9.9. 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: 2026-09-18 05:45:04.921Z (UTC).

Source advisory published: 2026-02-06 02:07:02.000Z (UTC).

This report uses published external intelligence. The advisory does not provide a separate source-code analysis for each listed version.