CVE-2021-26707

nodejs-merge-deep: Prototype pollution of Object.prototype via a constructor payload

Published 2 Jun 2021Modified 17 Jun 2026CWE 1321

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

GHSA9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Red Hat9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Trivy's own label is CRITICAL. Rated critical by NVD, GHSA. Rated lower by Red Hat (medium).

Description

The merge-deep library before 3.0.3 for Node.js can be tricked into overwriting properties of Object.prototype or adding new properties to it. These properties are then inherited by every object in the program, thus facilitating prototype-pollution attacks against applications using this library.

Affected packages and fixed versions

Source	Package	Fixed in
npm::GitHub Security Advisory npm	merge-deep	3.0.3
Red Hat	servicemesh-prometheus	no fix listed

References

All 9 references

https://www.npmjs.com/package/merge-deep

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