What’s Vulnerable › Vulnerabilities

CVE-2021-26707

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-02 · updated 2026-06-17
• Weakness: CWE-1321

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 products

• HackerOne merge-deep node module: before 3.0.3 — fixed in 3.0.3
• NetApp E-Series Performance Analyzer: all versions

How to fix

Upgrade to a fixed version: HackerOne merge-deep node module 3.0.3. Check the vendor advisory for mitigations.

References

• https://github.com/jonschlinkert/merge-deep/commit/11e5dd56de8a6aed0b1ed022089dbce6968d82a5
• https://security.netapp.com/advisory/ntap-20210716-0008/
• https://securitylab.github.com/advisories/GHSL-2020-160-merge-deep/
• https://www.npmjs.com/package/merge-deep
• https://github.com/jonschlinkert/merge-deep/commit/11e5dd56de8a6aed0b1ed022089dbce6968d82a5
• https://security.netapp.com/advisory/ntap-20210716-0008/
• https://securitylab.github.com/advisories/GHSL-2020-160-merge-deep/
• https://www.npmjs.com/package/merge-deep

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