Medium

Deep Merge is Vulnerable to Prototype Pollution Through Lack of Sanitization

  • Disclosed: 20.04.2026
  • Updated: 11.10.2026 10:22

A Prototype Pollution vulnerability was determined in brikcss merge up to 1.3.0. Executing a manipulation of the argument proto/constructor.prototype/prototype can lead to improperly controlled modification of object prototype attributes. The attack may be performed from remote. The vendor was contacted early about this disclosure but did not respond in any way.

Affected software

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PlatformPackageVulnerable versionsFixed in
npm package @brikcss/merge <= 1.3.1 no fix

References

CVSS score 7.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness (CWE)
CWE-1321, CWE-94
Platform
npm
Package
@brikcss/merge
Disclosed
20.04.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-3jc6-6r48-v6qf - CC BY 4.0

Vulnerability history: @brikcss/merge

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

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