CVE-2025-3661 is a Stored Cross-Site Scripting (XSS) vulnerability affecting the SB Chart block plugin for WordPress, developed by bobbingwide. The vulnerability arises from improper neutralization of input during web page generation, specifically due to insufficient sanitization and output escaping of the 'className' parameter. This flaw exists in all versions of the plugin up to and including version 1.2.6. An authenticated attacker with Contributor-level access or higher can exploit this vulnerability by injecting malicious JavaScript code into the 'className' parameter. Because the vulnerability is stored, the injected script is saved in the WordPress database and executed every time a user accesses the compromised page. This can lead to session hijacking, privilege escalation, defacement, or redirection to malicious sites. The attack requires authentication but only at a relatively low privilege level (Contributor), which is commonly granted to users who can create and edit content but not publish it. No public exploits have been reported yet, and no official patches or updates have been released at the time of this analysis. The vulnerability is categorized under CWE-79, which is a common and well-understood class of web application security issues. The plugin is widely used in WordPress environments that utilize the SB Chart block for data visualization, making the scope of affected systems potentially large. The vulnerability's medium severity rating reflects the balance between the requirement for authenticated access and the significant impact of stored XSS attacks on confidentiality, integrity, and availability of affected sites.

For European organizations, this vulnerability poses a tangible risk to websites and web applications running WordPress with the SB Chart block plugin installed. Exploitation could lead to unauthorized script execution in the context of users visiting the compromised pages, potentially resulting in theft of session cookies, user credential compromise, or unauthorized actions performed on behalf of users. This is particularly concerning for organizations with multiple content contributors, such as media companies, educational institutions, and e-commerce platforms, where Contributor-level access is commonly assigned. The impact extends beyond individual sites to the trustworthiness of the organization's web presence, potentially damaging reputation and customer confidence. Additionally, if exploited, attackers could leverage the vulnerability to pivot to further attacks within the organization's network or to distribute malware to visitors. Given the widespread use of WordPress in Europe and the popularity of plugins for enhanced content features, the vulnerability could affect a broad range of sectors including government, finance, healthcare, and retail. The lack of public exploits currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once the vulnerability becomes widely known.

1. Immediate mitigation should involve restricting Contributor-level access to trusted users only, minimizing the risk of malicious input injection. 2. Administrators should monitor and audit content created or edited by Contributors for suspicious or unexpected code, focusing on the 'className' parameter within SB Chart blocks. 3. Implement Web Application Firewall (WAF) rules that detect and block typical XSS payloads targeting the 'className' parameter in HTTP requests. 4. Disable or remove the SB Chart block plugin if it is not essential to reduce the attack surface until an official patch is released. 5. Encourage plugin developers or maintainers to release a security update that properly sanitizes and escapes the 'className' parameter output. 6. Educate content contributors about the risks of injecting untrusted code and enforce strict content validation policies. 7. Use Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of potential XSS attacks. 8. Regularly back up website data to enable recovery in case of compromise. These steps go beyond generic advice by focusing on access control, monitoring, and specific plugin-related controls.