PT-2019-12973 · Mybb · Mybb

Robin Peraglie + 1 · Published 2019-06-15 · Updated 2019-06-17 · CVE-2019-12831

Positive Technologies (AI Summary)

CVSS v3.1

7.2

High

Base vector

AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions MyBB versions prior to 1.8.21

Description The issue allows an attacker to create a PHP shell in the cache directory of a targeted forum via a crafted XML import. This is achieved by exploiting a default behavior of MySQL on many systems, where strings that are too long for a database column are truncated. For example, a string like aaaaaaaaaaaaaaaaaaaaaa.php.css can be truncated to aaaaaaaaaaaaaaaaaaaaaa.php due to a 30-character limit, leading to remote code execution.

Recommendations For MyBB versions prior to 1.8.21, update to version 1.8.21 or later to resolve the issue.

Exploit

Fix

RCE

Weakness Enumeration

CWE-20

Related Identifiers

CVE-2019-12831

Affected Products

Mybb

References · 4

• 🔥 https://blog.ripstech.com/2019/mybb-stored-xss-to-rce · Exploit
• https://osv.dev/vulnerability/CVE-2019-12831 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2019-12831 · Security Note
• https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-release · Vendor Advisory