CVE-2021-39338

medium
New! CVE Severity Now Using CVSS v3

The calculated severity for CVEs has been updated to use CVSS v3 by default. CVEs that do not have a CVSS v3 score will fall back CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

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.

References

https://github.com/BigTiger2020/word-press/blob/main/MyBB%20Cross-Poster.md

https://www.wordfence.com/vulnerability-advisories/#CVE-2021-39338

https://plugins.trac.wordpress.org/browser/mybb-cross-poster/trunk/classes/MyBBXPSettings.php

Details

Source: MITRE

Published: 2021-10-15

Updated: 2021-10-20

Type: CWE-79

Risk Information

CVSS v2

Base Score: 2.1

Vector: AV:N/AC:H/Au:S/C:N/I:P/A:N

Impact Score: 2.9

Exploitability Score: 3.9

Severity: LOW

CVSS v3

Base Score: 4.8

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Impact Score: 2.7

Exploitability Score: 1.7

Severity: MEDIUM

Vulnerable Software

Configuration 1

OR

cpe:2.3:a:mybb_cross-poster_project:mybb_cross-poster:*:*:*:*:*:wordpress:*:* versions up to 1.0 (inclusive)