Unauthorized Backdoor in myBB Web Application by MyBB Group
CVE-2011-10018

10CRITICAL

Key Information:

Vendor

Mybb Group

Status
Forum Software
Vendor
CVE Published:
13 August 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2011-10018?

The myBB version 1.6.4 was found to contain an unauthorized backdoor within its source code, allowing remote attackers to execute arbitrary PHP code. This vulnerability is exploited through specially crafted collapsed cookies, enabling an attacker to inject malicious payloads. The backdoor was inadvertently introduced during the application's packaging process, and exploitation does not require any authentication. Successful exploitation results in complete compromise of the web server, posing significant risks to users and administrators of the affected application.

Affected Version(s)

Forum Software 1.6.4

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2011-10018 - Proof of Concept

CVE-2011-10018 - Proof of Concept

References

https://raw.githubusercontent.com/rapid7/metasploit-frame...
exploit
https://www.exploit-db.com/exploits/17949
exploit
https://web.archive.org/web/20111015224948/http://secunia...
third-party-advisory

CVSS V4

Score:
10
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

MyBB
.
CVE-2011-10018 : Unauthorized Backdoor in myBB Web Application by MyBB Group