CVE-2025-11162 is a stored cross-site scripting vulnerability identified in the Spectra Gutenberg Blocks – Website Builder for the Block Editor plugin for WordPress, affecting all versions up to and including 2.19.14. The vulnerability arises from improper neutralization of input during web page generation, specifically within the Custom CSS feature. Authenticated users with Contributor-level access or higher can inject arbitrary JavaScript code into pages by exploiting insufficient input sanitization and lack of output escaping. Once injected, the malicious scripts execute in the context of any user who visits the compromised page, potentially allowing attackers to steal session cookies, perform actions on behalf of users, or deface the website. The vulnerability has a CVSS 3.1 base score of 6.4, reflecting medium severity, with an attack vector of network, low attack complexity, requiring privileges (Contributor or above), no user interaction, and scope change due to impact on other users. No public exploits are known at this time, but the vulnerability poses a risk to multi-user WordPress environments where contributors can add or edit content. The root cause is the plugin's failure to properly sanitize and escape CSS input, which is then rendered in pages viewed by others. This vulnerability highlights the risks of allowing relatively low-privileged users to inject code that is not properly validated or escaped. The Spectra plugin is widely used for building websites with the WordPress block editor, making this a relevant threat for many WordPress sites.

For European organizations, this vulnerability can lead to unauthorized script execution in the browsers of users visiting affected WordPress sites. Potential impacts include theft of authentication cookies, enabling session hijacking, unauthorized actions performed with user privileges, defacement of websites, and distribution of malware through injected scripts. Organizations relying on WordPress for public-facing websites or intranet portals with multiple contributors are particularly at risk. The compromise of user sessions can lead to data breaches or unauthorized access to sensitive information. Additionally, reputational damage and loss of customer trust may result from visible defacements or data leaks. Since the vulnerability requires Contributor-level access, insider threats or compromised contributor accounts increase risk. The medium severity rating reflects that while the vulnerability is not trivially exploitable by unauthenticated attackers, the potential for lateral impact and scope change is significant. European entities with strict data protection regulations (e.g., GDPR) must consider the compliance implications of any data exposure resulting from exploitation.

1. Monitor for and apply security updates from the plugin vendor as soon as patches become available to remediate the vulnerability. 2. Until patched, restrict Contributor-level access to trusted users only, minimizing the risk of malicious input injection. 3. Implement a web application firewall (WAF) with rules to detect and block common XSS attack patterns, especially those targeting CSS injection points. 4. Conduct regular security audits and code reviews of custom CSS or user-generated content to detect suspicious inputs. 5. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 6. Educate content contributors on security best practices and the risks of injecting untrusted code. 7. Consider disabling or limiting the Custom CSS feature for contributors if feasible. 8. Monitor website logs for unusual activity or unexpected changes in page content that could indicate exploitation attempts. 9. Use security plugins that provide additional input sanitization and output escaping for user-generated content. 10. Maintain strong authentication and session management controls to reduce the impact of session hijacking.