Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mybb | Mybb | < 1.8.39 |
Related Weaknesses (CWE)
References
- https://github.com/mybb/mybb/commit/6e6cfbd524d9101b51e1278ecf520479b64b0f00Patch
- https://github.com/mybb/mybb/security/advisories/GHSA-q4jv-xwjx-37cpVendor Advisory
- https://mybb.com/versions/1.8.39ProductRelease Notes
FAQ
What is CVE-2025-48940?
CVE-2025-48940 is a vulnerability with a CVSS score of 7.2 (HIGH). 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 sp...
How severe is CVE-2025-48940?
CVE-2025-48940 has been rated HIGH with a CVSS base score of 7.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-48940?
Check the references section above for vendor advisories and patch information. Affected products include: Mybb Mybb.