Authentication flaw

The isURLInPortal method in the URLTool class in inportal.py in Plone 2.1 through 4.1, 4.2.x through 4.2.5, and 4.3.x through 4.3.1 treats URLs starting with a space as a relative URL, which allows remote attackers to bypass the allowexternalloginsites filtering property, redirect users to...