CVE-2021-39338
5.5 MEDIUMThe MyBB Cross-Poster WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization...
Published: 2021-10-15 · Last updated: 2026-06-17
Severity and scoring
- CVSS
- 5.5 MEDIUM
- Vector
- CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
- CWE
- CWE-79
Affected products
| Vendor | Product |
|---|---|
| mybb_cross-poster_project | mybb_cross-poster |
Description
The MyBB Cross-Poster WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization via several parameters found in the ~/classes/MyBBXPSettings.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 1.0. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.
Source: NVD
References
- [NVD]https://nvd.nist.gov/vuln/detail/CVE-2021-39338
- [Exploit reference]https://github.com/BigTiger2020/word-press/blob/main/MyBB%20Cross-Poster.md
- [Patch]https://plugins.trac.wordpress.org/browser/mybb-cross-poster/trunk/classes/MyBBXPSettings.php
- [Other]https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39338
- [Exploit reference]https://github.com/BigTiger2020/word-press/blob/main/MyBB%20Cross-Poster.md
- [Patch]https://plugins.trac.wordpress.org/browser/mybb-cross-poster/trunk/classes/MyBBXPSettings.php
- [Other]https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39338
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