What’s Vulnerable › Vulnerabilities

CVE-2020-7637

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-04-06 · updated 2026-06-17
• Weakness: CWE-1321

Description

class-transformer before 0.3.1 allow attackers to perform Prototype Pollution. The classToPlainFromExist function could be tricked into adding or modifying properties of Object.prototype using a __proto__ payload.

Affected products

• class-transformer: before 0.3.1 — fixed in 0.3.1

How to fix

Upgrade to a fixed version: class-transformer 0.3.1. Check the vendor advisory for mitigations.

References

• https://github.com/typestack/class-transformer/commit/8f04eb9db02de708f1a20f6f2d2bb309b2fed01e
• https://snyk.io/vuln/SNYK-JS-CLASSTRANSFORMER-564431
• https://github.com/typestack/class-transformer/commit/8f04eb9db02de708f1a20f6f2d2bb309b2fed01e
• https://snyk.io/vuln/SNYK-JS-CLASSTRANSFORMER-564431

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