8.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7 High
AI Score
Confidence
High
0.006 Low
EPSS
Percentile
77.9%
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.
[
{
"vendor": "json5",
"product": "json5",
"versions": [
{
"version": "< 2.2.2",
"status": "affected"
}
]
}
]
github.com/json5/json5/issues/199
github.com/json5/json5/issues/295
github.com/json5/json5/pull/298
github.com/json5/json5/security/advisories/GHSA-9c47-m6qq-7p4h
lists.debian.org/debian-lts-announce/2023/11/msg00021.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3S26TLPLVFAJTUN3VIXFDEBEXDYO22CE/
8.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7 High
AI Score
Confidence
High
0.006 Low
EPSS
Percentile
77.9%