CVE-2026-4004 in Task Manager Plugin
Summary
by MITRE • 03/21/2026
The Task Manager plugin for WordPress is vulnerable to arbitrary shortcode execution via the 'search' AJAX action in all versions up to, and including, 3.0.2. This is due to missing capability checks in the callback_search() function and insufficient input validation that allows shortcode syntax (square brackets) to pass through sanitize_text_field() and be concatenated into a do_shortcode() call. This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary shortcodes on the site by injecting shortcode syntax into parameters like 'task_id', 'point_id', 'categories_id', or 'term'.
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Analysis
by VulDB Data Team • 03/21/2026
The vulnerability identified as CVE-2026-4004 affects the Task Manager plugin for WordPress, representing a critical security flaw that enables unauthorized code execution through manipulated shortcode parameters. This issue exists within the plugin's AJAX handling mechanism, specifically in the callback_search() function that processes search requests. The vulnerability impacts all versions up to and including 3.0.2, making it a widespread concern for WordPress installations that utilize this particular plugin. The flaw stems from inadequate input validation and insufficient capability checks that fail to properly sanitize user-supplied data before processing.
The technical implementation of this vulnerability occurs through a dangerous combination of missing authentication checks and improper input sanitization. When an authenticated user with subscriber-level privileges or higher submits a search request containing malicious shortcode syntax, the system fails to properly validate the input parameters. The sanitize_text_field() function, which should normally filter out potentially harmful content, is bypassed because it does not adequately prevent shortcode syntax from passing through. This allows attackers to inject square bracket notation directly into parameters such as task_id, point_id, categories_id, or term fields, which are then concatenated into a do_shortcode() function call. This creates a direct path for arbitrary shortcode execution, effectively transforming the legitimate search functionality into a code injection vector.
The operational impact of this vulnerability is significant as it provides attackers with the ability to execute arbitrary shortcodes on vulnerable WordPress sites. This capability allows for various malicious activities including but not limited to data exfiltration, site defacement, privilege escalation, and potential establishment of persistent backdoors. Attackers can leverage this vulnerability to execute any shortcode available within the WordPress environment, potentially accessing sensitive data, modifying content, or even installing malware. The fact that this vulnerability requires only subscriber-level access makes it particularly dangerous as it can be exploited by users who normally have limited privileges, potentially leading to more severe consequences than initially anticipated. The attack vector is particularly insidious because it leverages legitimate plugin functionality rather than exploiting unknown vulnerabilities or using advanced attack techniques.
Mitigation strategies for CVE-2026-4004 should focus on immediate remediation through plugin updates to versions that address the capability check and input validation issues. System administrators should implement the principle of least privilege by restricting user capabilities and ensuring that only authorized personnel have access to plugin management functions. Additionally, implementing proper input validation and capability checks within the plugin's AJAX handlers would prevent this type of exploitation. Organizations should also consider monitoring for unusual search patterns or shortcode execution attempts that might indicate exploitation attempts. The vulnerability aligns with CWE-89, which describes improper neutralization of special elements in SQL command, and reflects patterns similar to those found in ATT&CK technique T1566 related to phishing with malicious attachments. Regular security audits of WordPress plugins and maintaining updated security measures are essential to prevent similar vulnerabilities from being exploited in the future.