It was found in vanilla forums before 2.0.10 a cross-site scripting vulnerability where a filename could contain arbitrary code to execute on the client side.
In Vanilla before 2.6.1, the polling functionality allows Insecure Direct Object Reference (IDOR) via the Poll ID, leading to the ability of a single user to select multiple Poll Options (e.g., vote for multiple items).
Multiple cross-site scripting (XSS) vulnerabilities in Vanilla Forums before 2.0.18.13 and 2.1.x before 2.1.1 allow remote attackers to inject arbitrary web script or HTML via unspecified vectors.
The edit-profile page in Vanilla Forums before 2.1a32 allows remote authenticated users to modify arbitrary profile settings by replacing the UserID value during a man-in-the-middle attack, related to a "parameter manipulation" issue.