Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mybb | Mybb | < 1.8.21 |
Related Weaknesses (CWE)
References
- https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-releaRelease NotesVendor Advisory
- https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/ExploitVendor Advisory
- https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-releaRelease NotesVendor Advisory
- https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/ExploitVendor Advisory
FAQ
What is CVE-2019-12831?
CVE-2019-12831 is a vulnerability with a CVSS score of 7.2 (HIGH). 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 cach...
How severe is CVE-2019-12831?
CVE-2019-12831 has been rated HIGH with a CVSS base score of 7.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2019-12831?
Check the references section above for vendor advisories and patch information. Affected products include: Mybb Mybb.