CVE-2020-11753: 
Sonatype Nexus vulnerability analysis and mitigation

An improper access control vulnerability (CVE-2020-11753) was discovered in Sonatype Nexus Repository Manager versions 3.21.1 and 3.22.0. The vulnerability was disclosed on April 16th, 2020, and allows privileged users to create, modify, and execute scripting tasks without using the UI or API. Notably, in version 3.22.0, scripting is disabled by default, which mitigates the vulnerability's exploitability (Sonatype Advisory, NVD).

The vulnerability has been assigned a Critical severity rating with a CVSS v3.1 score of 9.1 (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H). The issue stems from improper access controls that allow authenticated users with appropriate privileges to bypass intended security restrictions for scripting tasks. The vulnerability is classified under CWE-863 (Incorrect Authorization) (Sonatype Advisory, NVD).

If exploited, the vulnerability allows privileged attackers to create, update, or execute scripts outside the typical use of the user interface or REST API. This could potentially lead to unauthorized script execution and system compromise within the scope of the authenticated user's privileges (Sonatype Advisory).

The vulnerability has been fixed in Nexus Repository OSS/Pro version 3.22.1. Sonatype strongly recommends all affected installations to upgrade to version 3.22.1 or later. For version 3.22.0, ensuring that scripting remains disabled provides an effective mitigation (Sonatype Advisory).

The vulnerability was identified by an external security researcher known as shadowsock5, who responsibly reported the issue to Sonatype. The company acknowledged the researcher's contribution in their advisory (Sonatype Advisory).