CVE-2025-9877 is a Stored Cross-Site Scripting (XSS) vulnerability identified in the Embed Google Datastudio WordPress plugin developed by elangovan. This vulnerability affects all versions up to and including 1.0.0 of the plugin. The root cause is insufficient input sanitization and output escaping on user-supplied attributes within the plugin's 'egds' shortcode. Specifically, authenticated users with contributor-level privileges or higher can inject arbitrary malicious scripts into pages using this shortcode. When other users access these compromised pages, the injected scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or other malicious activities. The vulnerability is classified under CWE-79, which pertains to improper neutralization of input during web page generation. The CVSS v3.1 base score is 6.4, indicating a medium severity level. The vector string (AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N) highlights that the attack can be performed remotely over the network with low attack complexity, requires privileges (contributor or higher), does not require user interaction, and impacts confidentiality and integrity with a scope change. No known exploits are currently reported in the wild, and no patches have been linked yet. This vulnerability is significant because WordPress is widely used for website content management, and plugins like Embed Google Datastudio are popular for embedding Google Data Studio reports. The ability for lower-privileged users to inject persistent scripts can undermine site security and user trust.

For European organizations, this vulnerability poses a risk primarily to websites using WordPress with the Embed Google Datastudio plugin installed. The impact includes potential unauthorized access to sensitive information via session hijacking or cookie theft, defacement of web content, and the possibility of further exploitation through chained attacks. Given the scope change indicated in the CVSS vector, the vulnerability can affect users beyond the initial attacker, potentially compromising multiple user accounts and data confidentiality. Organizations handling personal data under GDPR must be particularly cautious, as exploitation could lead to data breaches and regulatory penalties. Additionally, compromised websites can be used as vectors for phishing or malware distribution, damaging organizational reputation and trust. Since the vulnerability requires contributor-level access, insider threats or compromised user accounts increase risk. The lack of a patch at the time of publication means organizations must rely on mitigation strategies until an official fix is available.

1. Restrict contributor-level access strictly to trusted users and review user roles regularly to minimize risk exposure. 2. Implement Web Application Firewalls (WAF) with rules to detect and block suspicious script injections targeting the 'egds' shortcode or related plugin endpoints. 3. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected pages. 4. Monitor website content for unexpected script tags or unusual modifications, using automated scanning tools tailored for WordPress environments. 5. Educate content contributors about the risks of injecting untrusted content and enforce strict content validation policies. 6. Temporarily disable or remove the Embed Google Datastudio plugin if it is not essential until a patch is released. 7. Keep WordPress core and all plugins updated and subscribe to vendor or security mailing lists for timely patch notifications. 8. Conduct regular security audits and penetration testing focusing on plugin vulnerabilities and privilege escalation paths.