# CVE-2025-48940: MyBB's upgrade component vulnerable to local file inclusion

> Attackers can perform local file inclusion in MyBB's upgrade component if the installer is unlocked or accessible, potentially reading sensitive files.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Jun 2025
- **Updated:** 2 Jun 2025
- **Also known as:** GHSA-q4jv-xwjx-37cp

## What is CVE-2025-48940?

CVE-2025-48940 is a high-severity path traversal vulnerability in Mybb Mybb, published on 2 Jun 2025. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

MyBB is free and open source forum software. Prior to version 1.8.39, the upgrade component does not validate user input properly, which allows attackers to perform local file inclusion (LFI) via a specially crafted parameter value. In order to exploit the vulnerability, the installer must be unlocked (no `install/lock` file present) and the upgrade script must be accessible (by re-installing the forum via access to `install/index.php`; when the forum has not yet been installed; or the attacker is authenticated as a forum administrator). MyBB 1.8.39 resolves this issue.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2025-48940?

It affects 1 product.


Products: Mybb Mybb.

## How do I fix CVE-2025-48940?

No fix has been published for CVE-2025-48940 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-48940 being exploited?

There is no known exploitation of CVE-2025-48940 in the wild and no public exploit code.

## Other vulnerabilities in Mybb Mybb

- [CVE-2011-10018](https://insights.sbomify.com/CVE-2011-10018/): myBB 1.6.4 Backdoor Arbitrary Command Execution (critical 10.0)
- [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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-48940 and fix it if it is affected.

What it is: CVE-2025-48940 is a high-severity path traversal vulnerability in Mybb Mybb, published on 2 Jun 2025. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-48940 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-2025-48940/ (Markdown: https://insights.sbomify.com/CVE-2025-48940/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-48940
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-48940
- OSV: https://osv.dev/vulnerability/CVE-2025-48940

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-48940/
Summaries are generated and may contain mistakes; the official description above is the record.