CVE-2021-39338
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…
Does this matter?
Lower severity and a low EPSS score (0.95%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 4.8 MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 0.95% probability · 59th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- mybb cross-poster project/mybb cross-poster
- Source
- security@wordfence.com
References
- https://github.com/BigTiger2020/word-press/blob/main/MyBB%20Cross-Poster.mdExploit, Third Party Advisory
- https://plugins.trac.wordpress.org/browser/mybb-cross-poster/trunk/classes/MyBBXPSettings.phpPatch, Third Party Advisory
- https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39338Third Party Advisory
- https://github.com/BigTiger2020/word-press/blob/main/MyBB%20Cross-Poster.mdExploit, Third Party Advisory
- https://plugins.trac.wordpress.org/browser/mybb-cross-poster/trunk/classes/MyBBXPSettings.phpPatch, Third Party Advisory
- https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39338Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.