Intel

AIKIDO-2025-10838

@marcbachmann/cel-js is vulnerable to Prototype Pollution

Prototype Pollution Pre-CVE
Found by Aikido Intel before public disclosure or CVE publication.
Published Nov 26, 2025

73

High Risk

This Affects:

JS@marcbachmann/cel-js
2.0.4 - 5.2.0
Fixed in 5.2.1
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TL;DR

Affected versions of this package are vulnerable to Prototype Pollution through unsafe object creation where the code dynamically assigns properties without validating keys, allowing an attacker to exploit this by crafting malicious input that sets the __proto__, constructor, or prototype keys to pollute the base object prototype, potentially leading to denial of service, privilege escalation, or remote code execution by modifying inherited properties across the application.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range.

Background info

@marcbachmann/cel-js is vulnerable to Prototype Pollution in versions 2.0.4 - 5.2.0.

How to fix this

Upgrade the @marcbachmann/cel-js library to the patch version.