Jenkins Nexus Platform Plugin missing permission check

Jenkins Nexus Platform Plugin 3.18.0-03 and earlier does not perform permission checks in methods implementing form validation.

This allows attackers with Overall/Read permission to send an HTTP request to an attacker-specified URL and parse the response as XML.

Additionally, the plugin does not configure its XML parser to prevent XML external entity (XXE) attacks, so attackers can have Jenkins parse a crafted XML response that uses external entities for extraction of secrets from the Jenkins controller or server-side request forgery.

Additionally, these form validation methods do not require POST requests, resulting in a cross-site request forgery (CSRF) vulnerability.

Nexus Platform Plugin 3.18.1-01 configures its XML parser to prevent XML external entity (XXE) attacks.

Additionally, POST requests and Overall/Administer permission are required for the affected HTTP endpoints.