Remote Code Execution Vulnerability in MyBB Forum Software
CVE-2019-12831

7.2HIGH

Key Information:

Vendor

Mybb

Status
Mybb
Vendor
CVE Published:
15 June 2019

What is CVE-2019-12831?

MyBB versions prior to 1.8.21 are susceptible to a Remote Code Execution vulnerability that arises from improper handling of XML imports. By exploiting the default behavior of MySQL, which can truncate strings exceeding database column limits, an attacker can craft a malicious XML import. This enables the attacker to create a PHP shell within the cache directory of a targeted forum, effectively allowing them to execute arbitrary code on the server. The truncation issue can lead to arbitrary file creation, treating a file named 'aaaaaaaaaaaaaaaaaaaaaaaaaa.php.css' as 'aaaaaaaaaaaaaaaaaaaaaaaaaa.php', thus facilitating the RCE attack.

References

https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/
x_refsource_MISC
https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-sec...
x_refsource_MISC

CVSS V3.1

Score:
7.2
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.