What’s Vulnerable › Vulnerabilities

CVE-2019-20149: Validation Bypass in kind-of

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-12-30 · updated 2026-06-17
• Weakness: CWE-668

Description

ctorName in index.js in kind-of v6.0.2 allows external user input to overwrite certain internal attributes via a conflicting name, as demonstrated by 'constructor': {'name':'Symbol'}. Hence, a crafted payload can overwrite this builtin attribute to manipulate the type detection result.

Affected products

• Kind-Of Project Kind-Of: 6.0.2
• Npm Kind-Of: from 6.0.0 before 6.0.3 — fixed in 6.0.3

How to fix

Upgrade to a fixed version: Npm Kind-Of 6.0.3. Check the vendor advisory for mitigations.

References

• https://github.com/jonschlinkert/kind-of/issues/30
• https://github.com/jonschlinkert/kind-of/pull/31
• https://github.com/jonschlinkert/kind-of/issues/30
• https://github.com/jonschlinkert/kind-of/pull/31

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