Description
An issue was discovered in MediaWiki before 1.35.1. Missing users (accounts that don't exist) and hidden users (accounts that have been explicitly hidden due to being abusive, or similar) that the viewer cannot see are handled differently, exposing sensitive information about the hidden status to unprivileged viewers. This exists on various code paths.
Remediation
References
Related Vulnerabilities
WordPress Plugin WordPress File Upload Cross-Site Scripting (4.3.3)
WordPress Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2017-6514)
FrontAccounting Cross-site Request Forgery (CSRF) Vulnerability (CVE-2018-7176)
WordPress Plugin Duplicator-WordPress Migration Remote Code Execution (1.2.40)
WordPress Plugin Multilanguage by BestWebSoft Cross-Site Scripting (1.2.1)