This High severity Injection vulnerability was introduced in versions 10.3.23, and 11.3.8 of Jira Service Management Data Center.

This Injection vulnerability, with a CVSS Score of 8.8 and a CVSS Vector of CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H allows an authenticated attacker to modify the actions taken by a system call which has high impact to confidentiality, high impact to integrity, high impact to availability, and requires no user interaction.

Atlassian recommends that Jira Service Management Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:

• Jira Service Management Data Center 10.3: Upgrade to a release greater than or equal to 10.3.24

• Jira Service Management Data Center 11.3: Upgrade to a release greater than or equal to 11.3.10

See the release notes (https://confluence.atlassian.com/servicemanagement/jira-service-management-release-notes-780083086.html). You can download the latest version of Jira Service Management Data Center from the download center (https://www.atlassian.com/software/jira/service-management/download-archives).

The National Vulnerability Database provides the following description for this vulnerability: 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.