The wikitext parser in MediaWiki 1.17.x before 1.17.3 and 1.18.x before 1.18.2 allows remote attackers to cause a denial of service (infinite loop) via certain input, as demonstrated by the padleft function.

Multiple cross-site request forgery (CSRF) vulnerabilities in MediaWiki 1.17.x before 1.17.3 and 1.18.x before 1.18.2 allow remote attackers to hijack the authentication of users with the block permission for requests that (1) block a user via a request to the Block module or (2) unblock a user via a request to the Unblock module.

MediaWiki 1.17.x before 1.17.3 and 1.18.x before 1.18.2 uses weak random numbers for password reset tokens, which makes it easier for remote attackers to change the passwords of arbitrary users.

Cross-site scripting (XSS) vulnerability in the wikitext parser in MediaWiki 1.17.x before 1.17.3 and 1.18.x before 1.18.2 allows remote attackers to inject arbitrary web script or HTML via a crafted page with "forged strip item markers," as demonstrated using the CharInsert extension.

Cross-site scripting (XSS) vulnerability in the outputPage function in includes/SkinTemplate.php in MediaWiki before 1.17.5, 1.18.x before 1.18.4, and 1.19.x before 1.19.1 allows remote attackers to inject arbitrary web script or HTML via the uselang parameter to index.php/Main_page.