CVE-2022-46175
CVE-2022-46175
In short
JSON5 library versions before 1.0.2 and 2.2.2 allow attackers to inject malicious properties into parsed objects by using the `__proto__` key, potentially compromising application functionality. This happens because the library doesn't properly filter special keys, letting attackers modify object behavior in unexpected ways.
Technical detail
The JSON5.parse() method fails to sanitize the `__proto__` key during parsing, enabling prototype pollution of the returned object (not the global Object prototype). An attacker can craft malicious JSON5 strings containing `__proto__` entries to inject arbitrary properties; the impact depends on how the application uses the parsed object, potentially leading to XSS, DoS, privilege escalation, or RCE if the object is used in trusted operations.
Summary generated and translated by AI from the official 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.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:H