CVE-2019-6979 in User IP History Logs
Summary
by MITRE
An issue was discovered in the User IP History Logs (aka IP_History_Logs) plugin 1.0.2 for MyBB. There is XSS via the admin/modules/tools/ip_history_logs.php useragent field.
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Analysis
by VulDB Data Team • 08/30/2025
The vulnerability identified in CVE-2019-6979 affects the User IP History Logs plugin version 1.0.2 for the MyBB forum software platform, representing a cross-site scripting weakness that could enable attackers to execute malicious scripts within the context of administrative sessions. This issue specifically manifests in the admin/modules/tools/ip_history_logs.php endpoint where user agent data is processed without adequate input sanitization or output encoding, creating a persistent vector for malicious code injection.
The technical flaw stems from insufficient validation and sanitization of the useragent field within the administrative interface of the plugin. When administrators view IP history logs, the raw user agent strings are displayed without proper HTML escaping or context-appropriate encoding, allowing attackers to craft malicious user agent headers that contain script tags or other executable code. This vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, specifically targeting the web application's user interface rendering process rather than backend data processing.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with potential access to administrative functions and sensitive data within the MyBB platform. An attacker who successfully injects malicious scripts could potentially steal administrative session cookies, modify plugin configurations, or even escalate privileges within the forum environment. The vulnerability is particularly concerning because it targets the administrative interface, which typically has elevated privileges and access to critical system functions, making it a prime target for privilege escalation attacks.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, as it enables the execution of malicious JavaScript code within the browser context of authenticated administrators. The attack vector requires minimal privileges to exploit, as it only necessitates sending a specially crafted HTTP request with a malicious user agent string, which can be achieved through various means including compromised user accounts or direct network manipulation.
The recommended mitigations include immediate patching of the plugin to version 1.0.3 or later, which addresses the XSS vulnerability through proper input sanitization and output encoding of user agent data. Additionally, administrators should implement proper HTTP header validation to prevent malicious user agent strings from being processed, and consider implementing Content Security Policy headers to limit script execution within the administrative interface. Network-level protections such as web application firewalls can also provide additional defense-in-depth measures to detect and block malicious user agent strings before they reach the vulnerable endpoint, while regular security audits of installed plugins should be conducted to identify similar vulnerabilities in other third-party components.