MediaWiki before 1.27.4, 1.28.x before 1.28.3, and 1.29.x before 1.29.2, when a private wiki is configured, provides different error messages for failed login attempts depending on whether the username exists, which allows remote attackers to enumerate account names and conduct brute-force attacks via a series of requests.

api.php in MediaWiki before 1.27.4, 1.28.x before 1.28.3, and 1.29.x before 1.29.2 has a Reflected File Download vulnerability.

MediaWiki before 1.27.4, 1.28.x before 1.28.3, and 1.29.x before 1.29.2 has XSS when the $wgShowExceptionDetails setting is false and the browser sends non-standard URL escaping.

The implementation of raw message parameter expansion in MediaWiki before 1.27.4, 1.28.x before 1.28.3, and 1.29.x before 1.29.2 allows HTML mangling attacks.

MediaWiki 1.27.x before 1.27.1 might allow remote attackers to bypass intended session access restrictions by leveraging a call to the UserGetRights function after Session::getAllowedUserRights.

MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1 allows remote authenticated users with undelete permissions to bypass intended suppressrevision and deleterevision restrictions and remove the revision deletion status of arbitrary file revisions by using Special:Undelete.

MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1 does not generate head items in the context of a given title, which allows remote attackers to obtain sensitive information via a parse action to api.php.

Cross-site scripting (XSS) vulnerability in the Parser::replaceInternalLinks2 method in MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1 allows remote attackers to inject arbitrary web script or HTML via vectors involving replacement of percent encoding in unclosed internal links.

Cross-site scripting (XSS) vulnerability in the CSS user subpage preview feature in MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1 allows remote attackers to inject arbitrary web script or HTML via the edit box in Special:MyPage/common.css.

MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1, when $wgBlockDisablesLogin is true, might allow remote attackers to obtain sensitive information by leveraging failure to terminate sessions when a user account is blocked.

ApiParse in MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1 allows remote attackers to bypass intended per-title read restrictions via a parse action to api.php.

The (1) Special:MyPage, (2) Special:MyTalk, (3) Special:MyContributions, (4) Special:MyUploads, and (5) Special:AllMyUploads pages in MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1 allow remote attackers to obtain sensitive user login information via crafted links combined with page view statistics.

MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1 do not properly normalize IP addresses containing zero-padded octets, which might allow remote attackers to bypass intended access restrictions by using an IP address that was not supposed to have been allowed.

The User::randomPassword function in MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1 generates passwords smaller than $wgMinimalPasswordLength, which makes it easier for remote attackers to obtain access via a brute-force attack.

MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1 do not properly sanitize parameters when calling the cURL library, which allows remote attackers to read arbitrary files via an @ (at sign) character in unspecified POST array parameters.

The User::matchEditToken function in includes/User.php in MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1 does not perform token comparison in constant time before determining if a debugging message should be logged, which allows remote attackers to guess the edit token and bypass CSRF protection via a timing attack, a different vulnerability than CVE-2015-8623.

The User::matchEditToken function in includes/User.php in MediaWiki before 1.23.12 and 1.24.x before 1.24.5 does not perform token comparison in constant time before returning, which allows remote attackers to guess the edit token and bypass CSRF protection via a timing attack, a different vulnerability than CVE-2015-8624.

Cross-site scripting (XSS) vulnerability in MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1, when is configured with a relative URL, allows remote authenticated users to inject arbitrary web script or HTML via wikitext, as demonstrated by a wikilink to a page named "javascript:alert('XSS!')."

The MWOAuthDataStore::lookup_token function in Extension:OAuth for MediaWiki 1.25.x before 1.25.3, 1.24.x before 1.24.4, and before 1.23.11 does not properly validate the signature when checking the authorization signature, which allows remote registered Consumers to use another Consumer's credentials by leveraging knowledge of the credentials.

The OAuth extension for MediaWiki improperly negotiates a new client token only over Special:OAuth/initiate, which allows attackers to bypass intended IP address access restrictions by making an API request with an existing token.