Cross-site scripting (XSS) vulnerability in Microsoft SharePoint Server 2010 Gold and SP1, SharePoint Foundation 2010 Gold and SP1, and Office Web Apps 2010 Gold and SP1 allows remote attackers to inject arbitrary web script or HTML via crafted JavaScript elements in a URL, aka "SharePoint Script in Username Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15544
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-050