CVE-2021-23509: Prototype Pollution

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-11-03 · updated 2026-06-17
Weakness: CWE-843

Description

This affects the package json-ptr before 3.0.0. A type confusion vulnerability can lead to a bypass of CVE-2020-7766 when the user-provided keys used in the pointer parameter are arrays.

Affected products

json-ptr: before 3.0.0 — fixed in 3.0.0

How to fix

Upgrade to a fixed version: json-ptr 3.0.0. Check the vendor advisory for mitigations.

References

https://github.com/flitbit/json-ptr%23security-vulnerabilities-resolved
https://github.com/flitbit/json-ptr/commit/5dc458fbad1c382a2e3ca6d62e66ede3d92849ca
https://github.com/flitbit/json-ptr/pull/42
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1767165
https://snyk.io/vuln/SNYK-JS-JSONPTR-1577291
https://github.com/flitbit/json-ptr%23security-vulnerabilities-resolved
https://github.com/flitbit/json-ptr/commit/5dc458fbad1c382a2e3ca6d62e66ede3d92849ca
https://github.com/flitbit/json-ptr/pull/42
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1767165
https://snyk.io/vuln/SNYK-JS-JSONPTR-1577291

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