RCE in Mybb
CVE-2011-10018
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.
Vulnerability class: RCE (Remote Code Execution)
EPSS: 0.020 (78.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Mybb — versions 1.6.4
- Mybb Group Forum Software — versions 1.6.4
Weakness classification (CWE)
Public proof-of-concept exploits
References
- disclosure@vulncheck.com (Product, exploit)
- disclosure@vulncheck.com (Exploit, exploit)
- disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)
- disclosure@vulncheck.com (vendor-advisory, patch, Vendor Advisory)
- disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2011-10018?
- CVE-2011-10018 is a critical-severity vulnerability in Mybb, classified under Code Injection. CVSS score: 9.8/10. Published 2025-08-13.
- How severe is CVE-2011-10018?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2011-10018 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.