CVE-2024-21505

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-25 · updated 2026-06-17
Weakness: CWE-1321

Description

Versions of the package web3-utils before 4.2.1 are vulnerable to Prototype Pollution via the utility functions format and mergeDeep, due to insecure recursive merge. An attacker can manipulate an object's prototype, potentially leading to the alteration of the behavior of all objects inheriting from the affected prototype by passing specially crafted input to these functions.

Affected products

Web3-Utils: before 4.2.1 — fixed in 4.2.1

How to fix

Upgrade to a fixed version: Web3-Utils 4.2.1. Check the vendor advisory for mitigations.

References

https://github.com/web3/web3.js/commit/8ed041c6635d807b3da8960ad49e125e3d1b0e80
https://security.snyk.io/vuln/SNYK-JS-WEB3UTILS-6229337
https://github.com/web3/web3.js/commit/8ed041c6635d807b3da8960ad49e125e3d1b0e80
https://security.snyk.io/vuln/SNYK-JS-WEB3UTILS-6229337

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