GHSA-56p3-rrp4-2j82 Plone Open Redirection vulnerability via next parameter

• PyPI Plone: >= 2.1, < 4.1.1 → fixed in 4.1.1 • PyPI Plone: >= 4.2, < 4.2.6 → fixed in 4.2.6 • PyPI Plone: >= 4.3, < 4.3.2 → fixed in 4.3.2

The isURLInPortal method in the URLTool class in in_portal.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 allow_external_login_sites filtering property, redirect users to arbitrary web sites, and conduct phishing attacks via a space before a URL in the "next" parameter to acl_users/credentials_cookie_auth/require_login.