CVE-2022-46175
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (9.30%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 9.30% probability · 95th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-1321
- Affected
- json5/json5 · fedoraproject/fedora
- Source
- security-advisories@github.com
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/
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.