CVE-2011-10018

Critical

Description

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.

SeverityCritical

CVSS9.8

Exploit probability—

Product

Mybb

PublishedAug 13, 2025

First seenAug 13, 2025

Weakness typeCWE-912CWE-912 CWE-94Code injection

How to fix

Patches

blog.mybb.com/2011/10/06/1-6-4-security-vulnerabilit/

Affected products

Product	Affected versions	Fixed in
mybb mybb	1.6.4	—

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