CVE-2022-46175: JSON5 is an extension to the popular JSON file format that aims to be easier to write and maintain by hand (e.g. for config files). The `parse` method...

Description

JSON5 is an extension to the popular JSON file format that aims to be easier to write and maintain by hand (e.g. for config files). The `parse` method of the JSON5 library before and including versions 1.0.1 and 2.2.1 does not restrict parsing of keys named `__proto__`, allowing specially crafted strings to pollute the prototype of the resulting object. This vulnerability pollutes the prototype of the object returned by `JSON5.parse` and not the global Object prototype, which is the commonly understood definition of Prototype Pollution. However, polluting the prototype of a single object can have significant security impact for an application if the object is later used in trusted operations. This vulnerability could allow an attacker to set arbitrary and unexpected keys on the object returned from `JSON5.parse`. The actual impact will depend on how applications utilize the returned object and how they filter unwanted keys, but could include denial of service, cross-site scripting, elevation of privilege, and in extreme cases, remote code execution. `JSON5.parse` should restrict parsing of `__proto__` keys when parsing JSON strings to objects. As a point of reference, the `JSON.parse` method included in JavaScript ignores `__proto__` keys. Simply changing `JSON5.parse` to `JSON.parse` in the examples above mitigates this vulnerability. This vulnerability is patched in json5 versions 1.0.2, 2.2.2, and later.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

9.30%

94.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1321

Affected Software

Vendor	Product	Versions
Json5	Json5	< 1.0.2
Json5	Json5	>= 2.0.0, < 2.2.2
Fedoraproject	Fedora	37

References

https://github.com/json5/json5/issues/199Issue Tracking, Patch, Third Party Advisory
https://github.com/json5/json5/issues/295Issue Tracking, Third Party Advisory
https://github.com/json5/json5/pull/298Patch, Third Party Advisory
https://github.com/json5/json5/security/advisories/GHSA-9c47-m6qq-7p4hExploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/11/msg00021.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3S26TLPLVFAJTUN3VIXFDEBEXDYO22CE/
https://github.com/json5/json5/issues/199Issue Tracking, Patch, Third Party Advisory
https://github.com/json5/json5/issues/295Issue Tracking, Third Party Advisory
https://github.com/json5/json5/pull/298Patch, Third Party Advisory
https://github.com/json5/json5/security/advisories/GHSA-9c47-m6qq-7p4hExploit, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/11/msg00021.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3S26TLPLVFAJTUN3VIXFDEBEXDYO22CE/

Timeline

Published: Dec 24, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-46175?

JSON5 is an extension to the popular JSON file format that aims to be easier to write and maintain by hand (e.g. for config files). The `parse` method of the JSON5 library before and including versions 1.0.1 and 2.2.1 does not restrict parsing of keys named `__proto__`, allowing specially crafted strings to pollute the prototype of the resulting object. This vulnerability pollutes the prototype of the object returned by `JSON5.parse` and not the global Object prototype, which is the commonly understood definition of Prototype Pollution. However, polluting the prototype of a single object can have significant security impact for an application if the object is later used in trusted operations. This vulnerability could allow an attacker to set arbitrary and unexpected keys on the object returned from `JSON5.parse`. The actual impact will depend on how applications utilize the returned object and how they filter unwanted keys, but could include denial of service, cross-site scripting, elevation of privilege, and in extreme cases, remote code execution. `JSON5.parse` should restrict parsing of `__proto__` keys when parsing JSON strings to objects. As a point of reference, the `JSON.parse` method included in JavaScript ignores `__proto__` keys. Simply changing `JSON5.parse` to `JSON.parse` in the examples above mitigates this vulnerability. This vulnerability is patched in json5 versions 1.0.2, 2.2.2, and later.

How severe is CVE-2022-46175?

CVE-2022-46175 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 9.30% probability of exploitation in the next 30 days.

How do I fix CVE-2022-46175?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.