CVE-2025-48940CWE-22

MyBB's upgrade component vulnerable to local file inclusion

High · published June 2, 2025

CVSS v3.1
7.2
EPSS
1%
Percentile
44.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.2 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00541 · 44.7th percentile
Weakness
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Published
2025-06-02T15:52Z
EPSS history
Timeline
  • 02 JUN 15:52Z
    MyBB's upgrade component vulnerable to local file inclusion
    cvelistv5