CVE-2021-24834 in YOP Poll Plugin
Summary
by MITRE • 11/17/2021
The YOP Poll WordPress plugin before 6.3.1 is affected by a stored Cross-Site Scripting vulnerability which exists in the Create Poll - Options module where a user with a role as low as author is allowed to execute arbitrary script code within the context of the application. This vulnerability is due to insufficient validation of custom label parameters - vote button label , results link label and back to vote caption label.
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Analysis
by VulDB Data Team • 11/19/2021
The CVE-2021-24834 vulnerability represents a critical stored cross-site scripting flaw within the YOP Poll WordPress plugin ecosystem. This security weakness affects versions prior to 6.3.1 and demonstrates a significant oversight in input validation mechanisms. The vulnerability specifically targets the Create Poll - Options module where authors can manipulate custom label parameters including vote button label, results link label, and back to vote caption label. The flaw allows attackers with minimal privileges to inject malicious scripts that execute within the context of the application, potentially compromising user sessions and data integrity.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input within the plugin's administrative interface. When authors create polls and define custom labels for various interface elements, the plugin fails to properly validate or escape these parameters before storing them in the database. This stored XSS vulnerability enables attackers to craft malicious payloads that persist in the application's database and execute whenever the affected pages are rendered. The vulnerability's exploitation requires minimal privilege levels, making it particularly dangerous as it can be leveraged by users with author roles who typically have limited administrative capabilities.
The operational impact of CVE-2021-24834 extends beyond simple script execution, potentially enabling attackers to perform session hijacking, steal sensitive user information, or manipulate poll results. When malicious scripts execute within the context of the application, they can access cookies, local storage, and other browser resources that may contain authentication tokens or sensitive data. The stored nature of the vulnerability means that the malicious code remains persistent until manually removed, allowing attackers to maintain access to compromised systems over extended periods. This vulnerability directly aligns with CWE-79 which categorizes cross-site scripting flaws, and can be mapped to ATT&CK technique T1566.001 for initial access through malicious web content.
Organizations affected by this vulnerability should immediately implement patch management procedures to upgrade to YOP Poll plugin version 6.3.1 or later, which contains the necessary input validation fixes. Network administrators should monitor for suspicious activity in the plugin's administrative interfaces and implement web application firewalls to detect and block malicious payload delivery attempts. Additionally, security teams should conduct thorough audits of all WordPress installations to identify other plugins that may exhibit similar input validation deficiencies. The vulnerability highlights the importance of implementing proper input sanitization and output encoding practices throughout the application lifecycle, particularly in user-facing administrative modules where privilege levels vary significantly.