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 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.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
5.5 MEDIUM
NETWORK
LOW
HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
WordfenceCNA
5.5 MEDIUM
NETWORK
LOW
HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
CVEADP
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CISA-ADPADP
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Base Score
CVSS 3.x
EPSS Score
Percentile: 60%
VendorProductVersion
mybb_cross-poster_projectmybb_cross-poster
𝑥
≤ 1.0
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://github.com/BigTiger2020/word-press/blob/main/MyBB%20Cross-Poster.md
https://plugins.trac.wordpress.org/browser/mybb-cross-poster/trunk/classes/MyBBXPSettings.php
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39338
https://github.com/BigTiger2020/word-press/blob/main/MyBB%20Cross-Poster.md
https://plugins.trac.wordpress.org/browser/mybb-cross-poster/trunk/classes/MyBBXPSettings.php
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39338