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


- **Severity:** Critical 10.0 (`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`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 13 Aug 2025
- **Updated:** 7 Apr 2026
- **Also known as:** GHSA-4whv-mhhp-7qcj

## What is CVE-2011-10018?

CVE-2011-10018 is a critical vulnerability in Mybb Mybb, published on 13 Aug 2025. 

### Official 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.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-912 (Hidden Functionality)

## Which versions are affected by CVE-2011-10018?

It affects 1 product.


Products: Mybb Mybb.

## How do I fix CVE-2011-10018?

No fix has been published for CVE-2011-10018 yet. Limit exposure of the affected software until one is available.

## Is CVE-2011-10018 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2011-10018 exists.

Public exploit code:

- myBB 1.6.4 Backdoor Arbitrary Command Execution (metasploit)

## Other vulnerabilities in Mybb Mybb

- [CVE-2015-2786](https://insights.sbomify.com/CVE-2015-2786/): Information disclosure in n/a (critical 10.0)
- [CVE-2011-5133](https://insights.sbomify.com/CVE-2011-5133/): Cross-site scripting in n/a (critical 10.0)
- [CVE-2006-0218](https://insights.sbomify.com/CVE-2006-0218/): SQL injection in n/a (critical 10.0)
- [CVE-2020-22612](https://insights.sbomify.com/CVE-2020-22612/): Code injection in n/a (critical 9.8)
- [CVE-2017-16780](https://insights.sbomify.com/CVE-2017-16780/): Code injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-10018 and fix it if it is affected.

What it is: CVE-2011-10018 is a critical vulnerability in Mybb Mybb, published on 13 Aug 2025. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2011-10018 exists.

Affected product: Mybb Mybb. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2011-10018/ (Markdown: https://insights.sbomify.com/CVE-2011-10018/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-10018
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-10018
- OSV: https://osv.dev/vulnerability/CVE-2011-10018

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-10018/
Summaries are generated and may contain mistakes; the official description above is the record.