What’s Vulnerable › Vulnerabilities

CVE-2020-28499: Prototype Pollution

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-02-18 · updated 2026-06-17

Description

All versions of package merge are vulnerable to Prototype Pollution via _recursiveMerge .

Affected products

• @ianwalter/merge: before 2.1.1 — fixed in 2.1.1
• Npm Merge: before 2.1.1 — fixed in 2.1.1

How to fix

Upgrade to a fixed version: @ianwalter/merge 2.1.1; Npm Merge 2.1.1. Check the vendor advisory for mitigations.

References

• https://github.com/yeikos/js.merge/blob/master/src/index.ts%23L64
• https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1071049
• https://snyk.io/vuln/SNYK-JS-MERGE-1042987
• https://vuldb.com/?id.170146
• https://github.com/yeikos/js.merge/blob/master/src/index.ts%23L64
• https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1071049
• https://snyk.io/vuln/SNYK-JS-MERGE-1042987

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