CVE-2026-109512 in Mang Board Plugin
Summary
by MITRE • 10/16/2026
The Mang Board plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'content' parameter in all versions up to, and including, 2.4.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The sanitization bypass is further compounded by the ability to omit the data_type parameter in a modify request, which skips the HTMLPurifier branch entirely and leaves only mbw_htmlspecialchars2 encoding — fully reversed at render — as the sole barrier.
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Analysis
by VulDB Data Team • 10/16/2026
The Mang Board plugin for WordPress contains a critical stored cross-site scripting vulnerability affecting all versions up to and including 2.4.4, classified under CWE-79 in industry standards. This flaw stems from insufficient input sanitization and output escaping mechanisms within the application logic that handles user-generated content. The specific point of failure is located in the processing of the 'content' parameter during data modification requests. Because the vulnerability allows for persistent storage of malicious scripts on the server, it poses a significant risk to both site administrators and regular users who view the affected pages.
The technical nature of this flaw involves a bypass of standard security controls through specific request manipulation. The plugin attempts to mitigate injection attacks by utilizing HTMLPurifier when certain parameters are present in the input payload. However, attackers can circumvent this protection layer entirely by omitting the data_type parameter from their modify requests. When this parameter is absent, the application logic skips the robust sanitization branch provided by HTMLPurifier and defaults to a weaker encoding method known as mbw_htmlspecialchars2. This secondary defense mechanism proves inadequate against sophisticated attack vectors because it can be fully reversed at render time, effectively nullifying its protective value and leaving the injected script executable in the victim's browser context.
From an operational perspective, this vulnerability enables authenticated attackers with subscriber-level access or higher to inject arbitrary web scripts into pages that are subsequently viewed by other users. The impact is categorized under ATT&CK technique T1059 as command and scripting interpreter abuse, specifically targeting client-side code execution. Once the malicious script is stored on the server, it executes automatically whenever a user accesses the compromised page. This persistence allows for long-term exploitation without requiring repeated attacks against individual sessions. Potential consequences include session hijacking through cookie theft, defacement of the website interface, redirection to phishing sites, or further propagation of malware within the network environment if combined with other vulnerabilities.
Mitigation strategies must address both immediate remediation and long-term security posture improvements. The primary recommendation is to upgrade the Mang Board plugin to a version newer than 2.4.4 where these input validation issues have been resolved by the developers. In cases where upgrading is not immediately feasible, administrators should implement strict access controls to limit who can submit content modifications, ensuring that only trusted users with elevated privileges are allowed to interact with the affected endpoints. Additionally, deploying a Web Application Firewall capable of detecting and blocking cross-site scripting patterns in POST requests can provide an additional layer of defense against exploitation attempts while patches are being applied. Regular security audits focusing on input sanitization and output encoding practices across all plugins will help prevent similar vulnerabilities from arising in future updates or other components of the WordPress ecosystem.