CVE-2011-10018 CRITICAL

CVE-2011-10018: myBB 1.6.4 Backdoor Arbitrary Command Execution

Vendor Mybb Group
Product Forum Software
Weakness CWE-912
Published August 13, 2025
Last update April 7, 2026

CVSS base score

10.0/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

August 13, 2025 CVE published
April 7, 2026 Record updated