CVE-2019-12831

Description

In MyBB before 1.8.21, an attacker can abuse a default behavior of MySQL on many systems (that leads to truncation of strings that are too long for a database column) to create a PHP shell in the cache directory of a targeted forum via a crafted XML import, as demonstrated by truncation of aaaaaaaaaaaaaaaaaaaaaaaaaa.php.css to aaaaaaaaaaaaaaaaaaaaaaaaaa.php with a 30-character limit, aka theme import stylesheet name RCE.

Weakness classification

• nvd@nist.gov: CWE-20

Primary references

• cve@mitre.org — Release Notes, Vendor Advisory
• cve@mitre.org — Exploit, Vendor Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Release Notes, Vendor Advisory
• af854a3a-2127-422b-91ae-364da2661108 — Exploit, Vendor Advisory