CVE-2025-48940 - CVE House
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Status published High CVE-2025-48940

MyBB's upgrade component vulnerable to local file inclusion

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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

mybb
Vulnerable Versions:
< 1.8.39

Timeline

Official Publish: June 2nd, 2025
Last Modified: June 2nd, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Weaknesses (CWE)

CWE-22

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application
Initial Access
T1005 Data from Local System
Collection
T1552 Unsecured Credentials
Credential Access
T1565.001 Stored Data Manipulation
Impact