// For flags

CVE-2021-39338

MyBB Cross-Poster <= 1.0 Authenticated Stored Cross-Site Scripting

Severity Score

4.8
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

El plugin MyBB Cross-Poster de WordPress es vulnerable a un ataque de tipo Cross-Site Scripting Almacenado debido a una comprobación insuficiente y saneamiento de entradas por medio de diversos parámetros encontrados en el archivo ~/classes/MyBBXPSettings.php que permitían a atacantes con acceso de usuario administrativo inyectar scripts web arbitrarios, en versiones hasta la 1.0 incluyéndola. Esto afecta a las instalaciones multi-sitio en las que unfiltered_html está deshabilitado para los administradores, y a los sitios en los que unfiltered_html está deshabilitado

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.

*Credits: Thinkland Security Team
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
High
Authentication
Single
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-08-20 CVE Reserved
  • 2021-10-14 CVE Published
  • 2023-05-08 EPSS Updated
  • 2024-09-16 CVE Updated
  • 2024-09-16 First Exploit
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Mybb Cross-poster Project
Search vendor "Mybb Cross-poster Project"
 Mybb Cross-poster
Search vendor "Mybb Cross-poster Project" for product "Mybb Cross-poster"
 <= 1.0
Search vendor "Mybb Cross-poster Project" for product "Mybb Cross-poster" and version " <= 1.0"
wordpress
Affected