MediaWiki before 1.19.6 and 1.20.x before 1.20.5 does not allow extensions to prevent password changes without using both Special:PasswordReset and Special:ChangePassword, which allows remote attackers to bypass the intended restrictions of an extension that only implements one of these blocks.

MediaWiki before 1.19.6 and 1.20.x before 1.20.5 allows remote attackers to conduct cross-site scripting (XSS) attacks, as demonstrated by a CDATA section containing valid UTF-7 encoded sequences in a SVG file, which is then incorrectly interpreted as UTF-8 by Chrome and Firefox.

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.

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.

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 request forgery (CSRF) vulnerability in Special:Upload in MediaWiki 1.17.x before 1.17.3 and 1.18.x before 1.18.2 allows remote attackers to hijack the authentication of unspecified victims for requests that upload files.

The resource loader in MediaWiki 1.17.x before 1.17.3 and 1.18.x before 1.18.2 includes private data such as CSRF tokens in a JavaScript file, which allows remote attackers to obtain sensitive information.

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.

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.

MediaWiki before 1.17.1 does not check for read permission before handling action=ajax requests, which allows remote attackers to obtain sensitive information by (1) leveraging the SpecialUpload::ajaxGetExistsWarning function, or by (2) leveraging an extension, as demonstrated by the CategoryTree, ExtTab, and InlineEditor extensions.

MediaWiki before 1.17.1 allows remote attackers to obtain the page titles of all restricted pages via a series of requests involving the (1) curid or (2) oldid parameter.