Cross Site Scripting vulnerability in Mybb Mybb Forums v.1.8.33 allows a local attacker to execute arbitrary code via the theme Name parameter in the theme management component.

MyBB is a free and open source forum software. Custom MyCode (BBCode) for the visual editor (_SCEditor_) doesn't escape input properly when rendering HTML, resulting in a DOM-based XSS vulnerability. This weakness can be exploited by pointing a victim to a page where the visual editor is active (e.g. as a post or Private Message) and operates on a maliciously crafted MyCode message. This may occur on pages where message content is pre-filled using a GET/POST parameter, or on reply pages where a previously saved malicious message is quoted. The impact is be mitigated when: 1. the visual editor is disabled globally (_Admin CP → Configuration → Settings → Clickable Smilies and BB Code: [Clickable MyCode Editor](https://github.com/mybb/mybb/blob/mybb_1836/install/resources/settings.xml#L2087-L2094)_ is set to _Off_), or 2. the visual editor is disabled for individual user accounts (_User CP → Your Profile → Edit Options_: _Show the MyCode formatting options on the posting pages_ checkbox is not checked). MyBB 1.8.37 resolves this issue with the commit `6dcaf0b4d`. Users are advised to upgrade. Users unable to upgrade may mitigate the impact without upgrading MyBB by changing the following setting (_Admin CP → Configuration → Settings_): - _Clickable Smilies and BB Code → [Clickable MyCode Editor](https://github.com/mybb/mybb/blob/mybb_1836/install/resources/settings.xml#L2087-L2094)_: _Off_. Similarly, individual MyBB forum users are able to disable the visual editor by diabling the account option (_User CP → Your Profile → Edit Options_) _Show the MyCode formatting options on the posting pages_.

Installer RCE on settings file write in MyBB before 1.8.22.

MyBB before 1.8.36 allows Code Injection by users with certain high privileges. Templates in Admin CP intentionally use eval, and there was some validation of the input to eval, but type juggling interfered with this when using PCRE within PHP.

In MyBB before 1.8.34, there is XSS in the User CP module via the user email field.

MyBB before 1.8.33 allows Directory Traversal. The Admin CP Languages module allows remote authenticated users, with high privileges, to achieve local file inclusion and execution.

MyBB 1.8.31 has a SQL injection vulnerability in the Admin CP's Users module allows remote authenticated users to modify the query string via direct user input or stored search filter settings.

MyBB 1.8.31 has a (issue 2 of 2) cross-site scripting (XSS) vulnerabilities in the post Attachments interface allow attackers to inject HTML by persuading the user to upload a file with specially crafted name

MyBB 1.8.31 has a Cross-site scripting (XSS) vulnerability in the visual MyCode editor (SCEditor) allows remote attackers to inject HTML via user input or stored data

MyBB is a free and open source forum software. The _Mail Settings_ → Additional Parameters for PHP's mail() function mail_parameters setting value, in connection with the configured mail program's options and behavior, may allow access to sensitive information and Remote Code Execution (RCE). The vulnerable module requires Admin CP access with the `_Can manage settings?_` permission and may depend on configured file permissions. MyBB 1.8.31 resolves this issue with the commit `0cd318136a`. Users are advised to upgrade. There are no known workarounds for this vulnerability.

MyBB is a free and open source forum software. In affected versions the Admin CP's Settings management module does not validate setting types correctly on insertion and update, making it possible to add settings of supported type `php` with PHP code, executed on on _Change Settings_ pages. This results in a Remote Code Execution (RCE) vulnerability. The vulnerable module requires Admin CP access with the `Can manage settings?` permission. MyBB's Settings module, which allows administrators to add, edit, and delete non-default settings, stores setting data in an options code string ($options_code; mybb_settings.optionscode database column) that identifies the setting type and its options, separated by a new line character (\n). In MyBB 1.2.0, support for setting type php was added, for which the remaining part of the options code is PHP code executed on Change Settings pages (reserved for plugins and internal use). MyBB 1.8.30 resolves this issue. There are no known workarounds.

MyBB before 1.8.29 allows Remote Code Injection by an admin with the "Can manage settings?" permission. The Admin CP's Settings management module does not validate setting types correctly on insertion and update, making it possible to add settings of supported type "php" with PHP code, executed on Change Settings pages.

MyBB before 1.8.28 allows stored XSS because the displayed Template Name value in the Admin CP's theme management is not escaped properly.

Cross-site Scripting vulnerability in MyBB before 1.8.26 via Custom moderator tools.

SQL Injection vulnerability in MyBB before 1.8.26 via User Groups. (issue 3 of 3).

SQL Injection vulnerability in MyBB before 1.8.26 via the Copy Forum feature in Forum Management. (issue 2 of 3).

SQL Injection vulnerability in MyBB before 1.8.26 via poll vote count. (issue 1 of 3).

SQL Injection vulnerablity in MyBB before 1.8.26 via theme properties included in theme XML files.

Cross-site Scripting (XSS) vulnerability in MyBB before 1.8.26 via Nested Auto URL when parsing messages.

MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).