CVE-2020-15139: XSS in MyBB
First published: Mon Aug 10 2020(Updated: )
In MyBB before version 1.8.24, the custom MyCode (BBCode) for the visual editor doesn't escape input properly when rendering HTML, resulting in a DOM-based XSS vulnerability. The 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. After upgrading MyBB to 1.8.24, make sure to update the version attribute in the `codebuttons` template for non-default themes to serve the latest version of the patched `jscripts/bbcodes_sceditor.js` file.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Mybb Mybb | <1.8.24 |
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Reference Links
Frequently Asked Questions
What is CVE-2020-15139?
CVE-2020-15139 is a vulnerability in MyBB before version 1.8.24 that allows for a DOM-based XSS attack.
How does CVE-2020-15139 affect MyBB?
CVE-2020-15139 affects MyBB versions prior to 1.8.24.
What is the severity of CVE-2020-15139?
The severity of CVE-2020-15139 is high, with a CVSS score of 6.1.
How can CVE-2020-15139 be exploited?
CVE-2020-15139 can be exploited by directing a victim to a page where the MyBB visual editor is active.
How can I fix CVE-2020-15139?
To fix CVE-2020-15139, upgrade MyBB to version 1.8.24 or newer.
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