CVE-2011-10018

CRITICAL

myBB 1.6.4 - Unauthenticated Remote Code Execution via Collapsed Cookie Backdoor

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2011-10018. PoCs published by Metasploit, tdz, including Metasploit module exploits/unix/webapp/mybb_backdoor.

AI-analyzed exploit summary This exploit targets a backdoor in myBB 1.6.4, where a maliciously crafted cookie can execute arbitrary PHP code. The payload is encoded and sent via the 'collapsed' cookie parameter.

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.

Exploits (2)

exploitdb WORKING POC VERIFIED
by Metasploit · rubywebappsphp
https://www.exploit-db.com/exploits/17949

This exploit targets a backdoor in myBB 1.6.4, where a maliciously crafted cookie can execute arbitrary PHP code. The payload is encoded and sent via the 'collapsed' cookie parameter.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Trivial
Reliability
Reliable
Target: myBB 1.6.4
No auth needed
Prerequisites: Target must be running myBB 1.6.4 with the backdoor present
devstral-2 · analyzed Feb 16, 2026 Full analysis →
metasploit WORKING POC EXCELLENT
by tdz · rubypoc
https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/webapp/mybb_backdoor.rb

This Metasploit module exploits a backdoor in myBB 1.6.4 by injecting arbitrary PHP code via a maliciously crafted cookie. The payload is executed when the server processes the cookie, leading to remote command execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Trivial
Reliability
Reliable
Target: myBB 1.6.4
No auth needed
Prerequisites: Target must be running myBB 1.6.4 with the backdoor present
devstral-2 · analyzed Feb 16, 2026 Full analysis →

Scores

CVSS v3 9.8
EPSS 0.6812
EPSS Percentile 98.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Details

CWE
CWE-912 CWE-94
Status published
Products (2)
mybb/mybb 1.6.4
myBB Group/Forum Software 1.6.4
Published Aug 13, 2025
Tracked Since Feb 18, 2026