MyBB 1.6.4 backdoor

Summaryinfo

A vulnerability was found in MyBB 1.6.4. It has been classified as critical. Affected by this vulnerability is an unknown functionality. The manipulation leads to backdoor. This vulnerability is referenced as CVE-2011-10018. Remote exploitation of the attack is possible. Furthermore, an exploit is available.

Detailsinfo

A vulnerability was found in MyBB 1.6.4 and classified as critical. This issue affects an unknown code block. The manipulation with an unknown input leads to a backdoor vulnerability. Using CWE to declare the problem leads to CWE-912. The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

myBB version 1.6.4 was distributed with an unauthorized backdoor embedded in the source code. The backdoor allowed remote attackers to execute arbitrary PHP code by injecting payloads into a specially crafted collapsed cookie. This vulnerability was introduced during packaging and was not part of the intended application logic. Exploitation requires no authentication and results in full compromise of the web server under the context of the web application.

The advisory is shared at raw.githubusercontent.com. The identification of this vulnerability is CVE-2011-10018 since 08/13/2025. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are unknown but a public exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2025). MITRE ATT&CK project uses the attack technique T1588.001 for this issue.

The exploit is available at exploit-db.com. It is declared as proof-of-concept.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Exploit-DB (17949), EUVD (EUVD-2011-5246) and Secunia (SA46300†). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Content Management System

Name

• MyBB

Version

• 1.6.4

License

• open-source

Website

• Product: https://mybb.com/

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CPE 2.2info

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Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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