CVE-2025-28978 is a high-severity reflected Cross-site Scripting (XSS) vulnerability affecting the SB Breadcrumbs plugin developed by Hung Trang Si. This vulnerability arises due to improper neutralization of user-supplied input during web page generation, specifically in the way the plugin handles breadcrumb navigation data. Reflected XSS occurs when malicious input is immediately echoed back in the HTTP response without proper sanitization or encoding, allowing attackers to inject arbitrary JavaScript code that executes in the context of the victim's browser. The CVSS 3.1 base score of 7.1 reflects that the vulnerability can be exploited remotely over the network without authentication (AV:N/AC:L/PR:N), but requires user interaction (UI:R), and impacts confidentiality, integrity, and availability to a limited extent (C:L/I:L/A:L). The scope is changed (S:C), indicating that exploitation can affect components beyond the vulnerable SB Breadcrumbs plugin itself, potentially impacting the entire web application. Although no known exploits are currently reported in the wild, the vulnerability is publicly disclosed and poses a significant risk to websites using the affected versions of SB Breadcrumbs. The plugin version affected is up to 1.0, but the exact range is unspecified (noted as "n/a"), suggesting that all existing versions up to 1.0 are vulnerable. The vulnerability is categorized under CWE-79, which is a common and well-understood web application security flaw. The lack of available patches at the time of disclosure increases the urgency for mitigation. Attackers exploiting this vulnerability could execute malicious scripts that steal session cookies, perform actions on behalf of authenticated users, deface websites, or redirect users to malicious sites, thereby compromising user trust and data security.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on the SB Breadcrumbs plugin in their web infrastructure. Reflected XSS can lead to session hijacking, credential theft, and unauthorized actions within web applications, potentially exposing sensitive personal data protected under GDPR. This can result in regulatory penalties, reputational damage, and loss of customer trust. E-commerce platforms, government portals, and financial services websites using the vulnerable plugin are particularly at risk, as attackers could leverage this vulnerability to conduct phishing campaigns or escalate attacks within the network. Additionally, the scope change indicated by the CVSS vector suggests that exploitation could affect multiple components, increasing the risk of broader compromise. Given the interconnected nature of European digital services and the emphasis on data protection, organizations must prioritize addressing this vulnerability to maintain compliance and secure user interactions.

1. Immediate mitigation should involve disabling or removing the SB Breadcrumbs plugin until a secure patched version is released. 2. Implement Web Application Firewall (WAF) rules to detect and block typical reflected XSS attack patterns targeting breadcrumb parameters. 3. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS payloads. 4. Conduct thorough input validation and output encoding on all user-supplied data, especially in breadcrumb navigation components, to ensure special characters are properly escaped. 5. Monitor web server logs and application behavior for unusual requests or error patterns indicative of attempted exploitation. 6. Engage with the vendor or community to track the release of official patches and apply them promptly. 7. Educate developers and administrators about secure coding practices related to input handling and XSS prevention to avoid similar vulnerabilities in custom components. 8. For organizations using Content Management Systems (CMS) that integrate SB Breadcrumbs, review and harden plugin configurations and permissions to minimize attack surface.