CVE-2018-14392 in New Threads Plugin
Summary
by MITRE
The New Threads plugin before 1.2 for MyBB has XSS.
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Analysis
by VulDB Data Team • 07/28/2025
The vulnerability identified as CVE-2018-14392 affects the New Threads plugin version 1.1 and earlier for the MyBB forum software platform. This represents a cross-site scripting flaw that allows attackers to inject malicious scripts into web pages viewed by other users. The vulnerability specifically impacts the plugin's handling of user input within the forum environment, creating a persistent security risk for administrators and forum participants who may encounter malicious content during normal forum operations.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the New Threads plugin's codebase. When users create or interact with threads, the plugin fails to properly escape or filter user-supplied data before rendering it in web pages. This oversight creates an opportunity for attackers to craft malicious payloads that exploit the XSS vulnerability through various vectors including thread titles, post content, or user profile information. The flaw enables attackers to execute malicious scripts in the context of the victim's browser, potentially leading to session hijacking, credential theft, or unauthorized actions within the forum environment.
The operational impact of this vulnerability extends beyond simple script execution, as it can facilitate more sophisticated attacks within the MyBB ecosystem. Attackers can leverage the XSS vulnerability to steal administrator cookies, modify forum content, redirect users to malicious sites, or even establish persistent backdoors within the forum infrastructure. Given that MyBB forums often contain sensitive user information, including personal details and potentially confidential communications, the exploitation of this vulnerability could result in significant data breaches and compromise of user privacy. The vulnerability's persistence means that once exploited, malicious scripts can affect all users who view affected content until the plugin is updated or the vulnerability is patched.
Security practitioners should note that this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications. The attack surface for this vulnerability is particularly concerning within the ATT&CK framework, as it maps to techniques involving client-side exploitation and credential access. Organizations using MyBB platforms should prioritize immediate patching of the New Threads plugin to version 1.2 or later, as this represents the first fixed release addressing the XSS vulnerability. Additional mitigations include implementing content security policies, monitoring forum activity for suspicious content, and conducting regular security audits of third-party plugins to ensure continued protection against similar vulnerabilities. The vulnerability demonstrates the critical importance of input validation and output encoding practices in web application security, particularly when dealing with user-generated content in forum environments where trust boundaries are inherently blurred between administrators and community members.