CVE-2024-9885 in Widget or Sidebar Shortcode Plugin
Summary
by MITRE • 10/30/2024
The Widget or Sidebar Shortcode plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'sidebar' shortcode in all versions up to, and including, 0.6.1 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.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 03/02/2025
The Widget or Sidebar Shortcode plugin for WordPress presents a critical stored cross-site scripting vulnerability that affects all versions up to and including 0.6.1. This vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's sidebar shortcode implementation, creating a persistent security flaw that can be exploited by authenticated attackers. The issue specifically targets the plugin's handling of user-supplied attributes, allowing malicious input to be stored and subsequently executed without proper validation or sanitization. Attackers with contributor-level access or higher can leverage this weakness to inject malicious scripts that will execute whenever any user accesses a page containing the injected content, making this a particularly dangerous vulnerability in multi-user environments where contributors may have access to the WordPress admin interface.
The technical exploitation of this vulnerability occurs through the plugin's sidebar shortcode functionality, where user-supplied attributes are not properly sanitized before being stored in the database. When the shortcode is rendered on a webpage, the unsanitized input is output without adequate escaping, creating a stored XSS vector that can persist across multiple page views. This type of vulnerability falls under the CWE-79 category for cross-site scripting, specifically classified as a stored XSS flaw where malicious scripts are stored on the server and executed when accessed by other users. The vulnerability's impact is amplified by the fact that it requires only contributor-level privileges, which many WordPress installations grant to trusted users who may not be fully vetted security personnel, making the attack surface broader than initially apparent.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, data exfiltration, and privilege escalation within the WordPress environment. An attacker could inject scripts that steal administrator credentials, modify content, or redirect users to malicious sites, potentially compromising the entire WordPress installation. The persistent nature of stored XSS means that once the malicious code is injected, it will continue to execute for all users who access the affected pages, making it particularly dangerous in high-traffic environments where multiple users regularly view pages containing the vulnerable shortcode. This vulnerability also represents a significant risk to user trust and site reputation, as visitors may unknowingly be exposed to malicious code execution without any visible indication of compromise.
Organizations should immediately implement mitigations including updating to the latest version of the Widget or Sidebar Shortcode plugin where the vulnerability has been patched, or applying temporary workarounds such as restricting contributor-level access to shortcode usage or implementing additional input validation measures. Security teams should also conduct thorough audits of all installed plugins to identify similar vulnerabilities and implement comprehensive monitoring for unauthorized shortcode modifications. The ATT&CK framework categorizes this vulnerability under T1566 for Phishing and T1071 for Application Layer Protocol, highlighting the social engineering aspects of exploiting such vulnerabilities. Additionally, implementing proper input validation and output escaping practices in accordance with OWASP Top Ten security guidelines would prevent similar issues in future development cycles. Regular security assessments and plugin vulnerability scanning should be integrated into the organization's security posture to proactively identify and remediate such weaknesses before they can be exploited in real-world scenarios.