CVE-2025-5559 in TimeZoneCalculator Plugin
Summary
by MITRE • 06/26/2025
The TimeZoneCalculator plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'timezonecalculator_output' shortcode in all versions up to, and including, 3.37 due to insufficient input sanitization and output escaping on user supplied attributes. 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.
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Analysis
by VulDB Data Team • 06/26/2025
The TimeZoneCalculator plugin for WordPress presents a critical stored cross-site scripting vulnerability identified as CVE-2025-5559 that affects all versions up to and including 3.37. This vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's timezonecalculator_output shortcode implementation. The flaw specifically targets user-supplied attributes that are processed through the shortcode without proper validation or sanitization, creating an attack vector that can be exploited by authenticated users possessing contributor-level privileges or higher. The vulnerability's classification aligns with CWE-79, which addresses cross-site scripting flaws, and represents a significant security risk within WordPress ecosystems where plugin functionality can be leveraged to compromise user sessions and execute malicious code.
The technical exploitation of this vulnerability occurs when authenticated attackers with contributor-level access or greater insert malicious script code into the plugin's shortcode attributes. These attributes are then stored within the WordPress database and subsequently rendered on pages containing the shortcode, causing the malicious scripts to execute whenever any user accesses those pages. The stored nature of this XSS vulnerability means that the malicious payload persists even after the initial injection, making it particularly dangerous as it can affect multiple users over time. The vulnerability affects the plugin's output handling mechanism where user-supplied parameters are not properly escaped before being rendered in the HTML output, creating an environment where attacker-controlled scripts can be executed in the context of other users' browsers.
The operational impact of CVE-2025-5559 extends beyond simple script injection, as it provides attackers with potential access to sensitive user data and session information. When attackers can execute arbitrary scripts in users' browsers, they can potentially steal cookies, session tokens, or other sensitive information that could be used to escalate privileges or gain unauthorized access to administrative functions. The vulnerability's ability to affect pages containing the timezonecalculator_output shortcode means that any WordPress site utilizing this plugin becomes a potential target for persistent XSS attacks. The risk is particularly concerning for sites with multiple contributors or users who may inadvertently access compromised pages, as the malicious scripts can execute in the context of any user who views affected content, making this a widespread threat across various WordPress installations.
Mitigation strategies for CVE-2025-5559 should prioritize immediate plugin updates to versions that address the input sanitization and output escaping deficiencies. Organizations should implement strict input validation for all user-supplied data within the plugin's shortcode attributes, ensuring that any potentially malicious content is properly escaped before storage or rendering. The implementation of Content Security Policy headers can provide additional protection against script execution, while regular security audits of WordPress plugins should include verification of input handling and output escaping mechanisms. Security measures should also include monitoring for unauthorized modifications to plugin files and implementing role-based access controls that limit contributor-level access to only necessary functionality. According to ATT&CK framework category T1531, this vulnerability represents a technique for privilege escalation through the manipulation of application inputs, while the persistent nature of stored XSS aligns with T1189, which addresses content injection attacks. Organizations should also consider implementing web application firewalls to detect and block suspicious input patterns that could indicate exploitation attempts.