SEPTEMBER 19, 2026
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Case File

CVE-2026-45116

HIGH · CVSS 8.7 EPSS 0.30% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-18 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

The vulnerability affects MyBB forum software versions prior to 1.8.40, specifically in the user data handler, which fails to properly validate checkbox and multiselect profile field types, allowing for stored JavaScript code injection. This flaw can lead to the execution of malicious scripts when user data is rendered, posing a significant risk of cross-site scripting (XSS) attacks. Organizations using affected versions of MyBB should prioritize upgrading to version 1.8.40 to mitigate this high-severity security risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-45116
Severity
HIGH
CVSS
8.7
EPSS
0.30%
Java

Original NVD Description

MyBB is free and open source forum software. Prior to 1.8.40, the user datahandler does not properly validate checkbox and multiselect profile field types, resulting in stored JavaScript code injection. UserDataHandler::verify_profile_fields() only performs the specialized validation when is_array($profile_fields[$field]) is true. A non-array profile_fields[fidX] value instead of the expected profile_fields[fidX][] shape falls through to generic text handling and is stored without verification. The affected value is then rendered directly by member.php and inc/functions_post.php rather than processed by the MyCode parser. The uniquely identifying implementation details include inc/datahandlers/user.php. This issue is fixed in version 1.8.40.