CVE-2025-12711 identifies a stored Cross-Site Scripting (XSS) vulnerability in the Share to Google Classroom plugin for WordPress, developed by pritenhshah. This vulnerability arises from improper neutralization of user input during web page generation, specifically within the share_to_google shortcode. The plugin fails to adequately sanitize and escape user-supplied attributes, allowing authenticated users with Contributor-level permissions or higher to inject arbitrary JavaScript code into WordPress pages. Because the injected scripts are stored persistently, they execute every time a user accesses the affected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions on behalf of users. The vulnerability is exploitable remotely over the network without user interaction but requires the attacker to have at least Contributor-level privileges, which are commonly assigned to trusted users who can add or edit content. The CVSS 3.1 base score is 6.4, reflecting medium severity due to the combination of network attack vector, low attack complexity, and privileges required. The scope is changed (S:C) because the vulnerability affects components beyond the initially vulnerable plugin, potentially impacting the entire WordPress site. No patches or fixes have been officially released at the time of publication, and no known exploits have been observed in the wild. The vulnerability is particularly relevant for organizations using WordPress sites integrated with Google Classroom, especially educational institutions and e-learning platforms. Attackers exploiting this vulnerability could perform persistent XSS attacks, leading to data theft, session hijacking, or further compromise of the WordPress environment.

For European organizations, especially educational institutions and e-learning platforms that utilize WordPress with the Share to Google Classroom plugin, this vulnerability poses a significant risk. Exploitation could lead to unauthorized access to user sessions, theft of sensitive information such as authentication tokens or personal data, and potential defacement or manipulation of website content. The persistent nature of the stored XSS means that all users visiting the compromised pages are at risk, amplifying the impact. This can undermine trust in educational platforms, lead to data privacy violations under GDPR, and cause operational disruptions. Additionally, attackers could leverage the foothold gained through XSS to escalate privileges or deploy further malware within the affected WordPress environment. Given the widespread use of WordPress in Europe and the growing reliance on digital education tools, the threat could affect a broad range of organizations if not mitigated promptly.

To mitigate this vulnerability, European organizations should take the following specific actions: 1) Immediately audit WordPress sites for the presence of the Share to Google Classroom plugin and identify versions in use. 2) Restrict Contributor-level and higher permissions to trusted users only, minimizing the risk of malicious shortcode injection. 3) Implement strict input validation and output escaping for all shortcode attributes, either by applying custom filters or using security plugins that enforce sanitization. 4) Monitor site content for suspicious or unexpected shortcode usage that could indicate exploitation attempts. 5) Employ Web Application Firewalls (WAFs) configured to detect and block XSS payloads targeting the affected shortcode. 6) Regularly back up WordPress sites to enable quick restoration if compromise is detected. 7) Stay informed about official patches or updates from the plugin developer and apply them promptly once available. 8) Educate content contributors about the risks of injecting untrusted code and enforce security best practices in content management. These targeted measures go beyond generic advice by focusing on permission management, content monitoring, and proactive detection tailored to this specific vulnerability.