# CVE-2016-9420: Security feature bypass in n/a

> Remote attackers can bypass security checks in MyBB forum software due to loose comparison errors, potentially compromising application integrity.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Jan 2017
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-8g78-7gc4-jx8q

## What is CVE-2016-9420?

CVE-2016-9420 is a critical vulnerability in Mybb Mybb, published on 31 Jan 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

MyBB (aka MyBulletinBoard) before 1.8.8 and MyBB Merge System before 1.8.8 allow remote attackers to have unspecified impact via vectors related to "loose comparison false positives."

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2016-9420?

It affects 2 products.


Products: Mybb Merge System, Mybb Mybb.

## How do I fix CVE-2016-9420?

No fix has been published for CVE-2016-9420 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-9420 being exploited?

There is no known exploitation of CVE-2016-9420 in the wild and no public exploit code.

## Other vulnerabilities in Mybb Mybb

- [CVE-2015-8974](https://insights.sbomify.com/CVE-2015-8974/): SQL injection in n/a (critical 10.0)
- [CVE-2016-9402](https://insights.sbomify.com/CVE-2016-9402/): SQL injection in n/a (critical 9.8)
- [CVE-2016-9403](https://insights.sbomify.com/CVE-2016-9403/): newreply.php in MyBB (aka MyBulletinBoard) before 1.8.7 and MyBB Merge System before 1.8.7 allows remote attackers to have unspecified impac (critical 9.8)
- [CVE-2016-9412](https://insights.sbomify.com/CVE-2016-9412/): Weak cryptography in n/a (critical 9.8)
- [CVE-2016-9416](https://insights.sbomify.com/CVE-2016-9416/): SQL injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-9420 and fix it if it is affected.

What it is: CVE-2016-9420 is a critical vulnerability in Mybb Mybb, published on 31 Jan 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-9420 in the wild and no public exploit code.

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-2016-9420/ (Markdown: https://insights.sbomify.com/CVE-2016-9420/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-9420
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-9420
- OSV: https://osv.dev/vulnerability/CVE-2016-9420

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-9420/
Summaries are generated and may contain mistakes; the official description above is the record.