MyBB 1.8.32 Authenticated Remote Code Execution via Chained Vulnerabilities

Advisories

severity: high
date: December 22, 2025
Affecting: MyBB MyBB 1.8.32
CVE: CVE-2023-53979
CWE: CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVSS: 8.6
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References: ExploitDB-51213
Official MyBB Vendor Homepage
Researcher Disclosure
Credit: lUc1f3r11
Description: MyBB 1.8.32 contains a chained vulnerability that allows authenticated administrators to bypass avatar upload restrictions and execute arbitrary code. Attackers can modify upload path settings, upload a malicious PHP-embedded image file, and execute commands through the language configuration editing interface.