CVE-2026-6642 in Media Library Assistant Plugin
Summary
by MITRE • 09/11/2026
The Media Library Assistant plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the bulk edit preset export/import mechanism in versions up to and including 3.35. This is due to insufficient output escaping on preset field values when they are rendered in HTML attribute contexts in the mla_generate_bulk_edit_form_fieldsets() function and mla-bulk-edit-fieldsets.tpl template. While wp_kses() filtering is applied during preset export for users without unfiltered_html capability, this does not prevent attribute injection attacks since the malicious payload consists of quotes and HTML attributes rather than HTML tags. When preset values are retrieved and rendered, they are directly assigned to template variables without esc_attr() escaping and then inserted into input element value attributes via simple string replacement. This makes it possible for authenticated attackers, with Author-level access and above (upload_files capability), to inject arbitrary web scripts that execute when an administrator imports the poisoned preset and the targeted input field receives focus.
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Analysis
by VulDB Data Team • 09/11/2026
The Media Library Assistant plugin for WordPress contains a critical stored cross-site scripting vulnerability affecting versions up through 3.35, specifically within its bulk edit preset export and import functionality. This security flaw stems from insufficient output escaping when handling preset field values during their rendering in HTML attribute contexts. The technical root cause is located primarily within the mla_generate_bulk_edit_form_fieldsets function and the associated mla-bulk-edit-fieldsets.tpl template file. While the plugin implements wp_kses filtering to sanitize data upon export for users lacking unfiltered_html capabilities, this measure proves ineffective against specific injection vectors because it targets HTML tags rather than attribute-based attacks. Attackers can bypass these filters by crafting payloads that consist of quotes and additional HTML attributes instead of standard script tags, allowing malicious code to persist within the stored preset data without triggering immediate detection mechanisms during the export phase.
The operational impact arises when an administrator with sufficient privileges imports a poisoned preset file generated by an attacker. Upon import, the vulnerable template variables are assigned directly from the unescaped preset values and subsequently inserted into input element value attributes using simple string replacement techniques that lack proper context-aware escaping functions such as esc_attr(). This architectural oversight means that any malicious payload embedded in these fields remains intact within the database until it is rendered back to a user interface. Consequently, when an administrator views or interacts with the bulk edit form containing the compromised preset, and specifically focuses on the targeted input field, the browser interprets the injected content as executable JavaScript rather than plain text data. This execution environment allows for arbitrary web script injection that operates within the context of the victim's session cookies and privileges.
From a classification perspective, this vulnerability aligns with CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting (XSS). The stored nature of the attack vector places it firmly in the category where malicious scripts are permanently stored on vulnerable web applications and executed whenever users access affected pages. In terms of adversary tactics, this flaw facilitates exploitation consistent with ATT&CK technique T1059, specifically subcategory 007 for JavaScript execution via browser-based interfaces. The requirement for authenticated access means that threat actors must first compromise or obtain credentials for an account possessing at least Author-level permissions and the upload_files capability to create and distribute the malicious preset files.
Mitigation strategies should prioritize immediate upgrading of the Media Library Assistant plugin to a version where this vulnerability has been patched, ensuring that all output escaping mechanisms are correctly implemented using WordPress standard functions like esc_attr() before data is rendered in HTML attributes. For organizations unable to upgrade immediately due to compatibility constraints, implementing strict input validation and context-aware output encoding at the application layer can provide temporary relief. Additionally, enforcing Content Security Policy headers with nonces or hashes for admin areas can help mitigate the impact of successful script injection by restricting inline script execution unless explicitly allowed. Regular security audits focusing on template rendering logic and data flow between database storage and user interface presentation are essential to prevent similar attribute-based XSS vulnerabilities in future development cycles.