Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mybb | Mybb | < 1.8.24 |
Related Weaknesses (CWE)
References
- https://github.com/mybb/mybb/commit/37ad29dcd25489a37bdd89ebac761f22492558b0PatchThird Party Advisory
- https://github.com/mybb/mybb/security/advisories/GHSA-37h7-vfv6-f8rjPatchThird Party Advisory
- https://mybb.com/versions/1.8.24/PatchVendor Advisory
- https://github.com/mybb/mybb/commit/37ad29dcd25489a37bdd89ebac761f22492558b0PatchThird Party Advisory
- https://github.com/mybb/mybb/security/advisories/GHSA-37h7-vfv6-f8rjPatchThird Party Advisory
- https://mybb.com/versions/1.8.24/PatchVendor Advisory
FAQ
What is CVE-2020-15139?
CVE-2020-15139 is a vulnerability with a CVSS score of 8.8 (HIGH). 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 explo...
How severe is CVE-2020-15139?
CVE-2020-15139 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2020-15139?
Check the references section above for vendor advisories and patch information. Affected products include: Mybb Mybb.