MyBB up to 1.8.36 Visual Editor cross site scripting

Summaryinfo

A vulnerability categorized as problematic has been discovered in MyBB up to 1.8.36. This affects an unknown function of the component Visual Editor. The manipulation results in cross site scripting. This vulnerability is known as CVE-2023-46251. It is possible to launch the attack remotely. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in MyBB up to 1.8.36 (Content Management System). Affected is an unknown functionality of the component Visual Editor. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

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_.

The weakness was published 11/06/2023. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2023-46251 since 10/19/2023. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 1.8.37 eliminates this vulnerability.

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Productinfo

Type

• Content Management System

Name

• MyBB

Version

• 1.8.0
• 1.8.1
• 1.8.2
• 1.8.3
• 1.8.4
• 1.8.5
• 1.8.6
• 1.8.7
• 1.8.8
• 1.8.9
• 1.8.10
• 1.8.11
• 1.8.12
• 1.8.13
• 1.8.14
• 1.8.15
• 1.8.16
• 1.8.17
• 1.8.18
• 1.8.19
• 1.8.20
• 1.8.21
• 1.8.22
• 1.8.23
• 1.8.24
• 1.8.25
• 1.8.26
• 1.8.27
• 1.8.28
• 1.8.29
• 1.8.30
• 1.8.31
• 1.8.32
• 1.8.33
• 1.8.34
• 1.8.35
• 1.8.36

License

• open-source

Website

• Product: https://mybb.com/

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