What’s Vulnerable › Vulnerabilities

CVE-2020-7770: Prototype Pollution

• 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: yes
• Published: 2020-11-12 · updated 2026-06-17
• Weakness: CWE-1321

Description

This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.

Affected products

• json8: before 1.0.3 — fixed in 1.0.3

How to fix

Upgrade to a fixed version: json8 1.0.3. Check the vendor advisory for mitigations.

References

• https://github.com/sonnyp/JSON8/commit/2e890261b66cbc54ae01d0c79c71b0fd18379e7e
• https://snyk.io/vuln/SNYK-JS-JSON8-1017116
• https://github.com/sonnyp/JSON8/commit/2e890261b66cbc54ae01d0c79c71b0fd18379e7e
• https://snyk.io/vuln/SNYK-JS-JSON8-1017116

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