CVE-2019-12831

Public Exploit

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.

Category

7.2
CVSS
Severity: High
CVSS 3.0 •
CVSS 2.0 •
EPSS 0.55%
Vendor Advisory mybb.com Vendor Advisory ripstech.com
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/ vendor advisory exploit
https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-release/ release notes vendor advisory

Frequently Asked Questions

What is the severity of CVE-2019-12831?
CVE-2019-12831 has been scored as a high severity vulnerability.
How to fix CVE-2019-12831?
To fix CVE-2019-12831, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2019-12831 being actively exploited in the wild?
It is possible that CVE-2019-12831 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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