In JForum 2.1.8, an unauthenticated, remote attacker can enumerate whether a user exists by using the "create user" function. If a register/check/username?username= request corresponds to a username that exists, then an "is already in use" error is produced. NOTE: this product is discontinued.

WikidForum 2.20 has SQL Injection via the rpc.php parent_post_id or num_records parameter, or the index.php?action=search select_sort parameter.

my little forum 2.4.12 allows CSRF for deletion of users.

The Add page option in my little forum 2.4.12 allows XSS via the Title field.

The Add page option in my little forum 2.4.12 allows XSS via the Menu Link field.

LogInOut.php in Simple Machines Forum (SMF) 2.1 allows remote attackers to conduct PHP object injection attacks and execute arbitrary PHP code via vectors related to variables derived from user input in a foreach loop.

Packages.php in Simple Machines Forum (SMF) 2.1 allows remote attackers to conduct PHP object injection attacks and execute arbitrary PHP code via the themechanges array parameter.

The sanitize function in Codoforum 2.5.1 does not properly implement filtering for directory traversal sequences, which allows remote attackers to read arbitrary files via a .. (dot dot) in the path parameter to index.php.

Multiple cross-site scripting (XSS) vulnerabilities in my little forum 2.3.3, 2.2, and 1.7 allow remote attackers to inject arbitrary web script or HTML via the (1) page or (2) category parameter to forum.php or the (3) page or (4) order parameter to (a) board_entry.php or (b) forum_entry.php.

The Mark's Daily Apple Forum (aka com.tapatalk.marksdailyapplecomforum) application 2.4.9.3 for Android does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.