CVE-2026-16685 in Download Manager Plugin
Summary
by MITRE • 08/01/2026
The Download Manager plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'icon' Shortcode Attribute in all versions up to, and including, 3.3.66 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. wp_kses_post() does not neutralize the payload because it operates on post content at save time and does not process shortcode attribute values that are emitted unescaped at render time.
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Analysis
by VulDB Data Team • 08/01/2026
The vulnerability in the Download Manager plugin for WordPress represents a critical stored cross-site scripting flaw that affects versions up to and including 3.3.66. This security weakness stems from inadequate input sanitization and output escaping mechanisms within the plugin's shortcode processing functionality. The issue specifically impacts the 'icon' shortcode attribute, creating a persistent vector for malicious code injection that can compromise user sessions and execute unauthorized commands.
Attackers with contributor-level access or higher can exploit this vulnerability by injecting malicious scripts through the icon shortcode parameter. When legitimate users access pages containing the injected content, the stored payload executes in their browsers, potentially leading to session hijacking, data theft, or further exploitation of the compromised systems. The vulnerability operates at the intersection of improper input validation and insufficient output escaping, creating a dangerous combination that bypasses standard WordPress security measures.
The technical root cause lies in how wp_kses_post() function processes content during save operations rather than during rendering time. This approach fails to address shortcode attribute values that are emitted unescaped when pages are rendered, allowing malicious payloads to persist in the database and execute whenever affected pages are accessed. The flaw demonstrates a classic security anti-pattern where sanitization occurs at an inappropriate processing stage, leaving the application vulnerable during the execution phase of user interactions.
This vulnerability directly maps to CWE-79: Cross-site Scripting and aligns with ATT&CK technique T1566.002: Phishing via Service Provider for credential theft and session manipulation. The attack surface expands significantly given that contributors can leverage this weakness, potentially compromising entire WordPress installations through social engineering or privilege escalation attacks.
Organizations should implement immediate mitigations including plugin version updates to the latest secure release, implementing additional input validation layers, and conducting thorough security audits of all installed plugins. Network monitoring should be enhanced to detect suspicious shortcode usage patterns, while user access controls should be reviewed to minimize potential attack vectors. The vulnerability underscores the critical importance of proper sanitization at all processing stages rather than relying solely on post-save content filtering mechanisms.