The bbcode plugin in TinyMCE 3.5.8 does not properly enforce the TinyMCE security policy for the (1) encoding directive and (2) valid_elements attribute, which allows attackers to conduct cross-site scripting (XSS) attacks via application-specific vectors, as demonstrated using a textarea element.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.006
EPSS Ranking 68.9%