CVE-2026-0594 is a reflected Cross-Site Scripting (XSS) vulnerability identified in the List Site Contributors plugin for WordPress, affecting all versions up to and including 1.1.8. The vulnerability stems from improper neutralization of input during web page generation, specifically inadequate sanitization and escaping of the 'alpha' parameter. This flaw allows unauthenticated attackers to craft malicious URLs containing JavaScript payloads that, when clicked by a victim, execute within the context of the vulnerable website. The attack vector requires no authentication but does require user interaction in the form of clicking a malicious link. The vulnerability impacts confidentiality and integrity by enabling theft of session cookies, user credentials, or execution of unauthorized actions on behalf of the victim. Availability is not affected. The CVSS v3.1 base score is 6.1, reflecting medium severity with network attack vector, low attack complexity, no privileges required, user interaction required, and a scope change due to potential impact beyond the vulnerable component. No public exploits have been reported yet, but the presence of this vulnerability in a widely used CMS plugin poses a significant risk, especially for sites relying on the plugin for contributor listings. The vulnerability is categorized under CWE-79, a common web application security weakness. Technical details confirm the vulnerability was reserved and published in early January 2026, with no patch links currently available, indicating the need for vigilance and interim mitigations.

For European organizations, the impact of CVE-2026-0594 can be significant, particularly for those operating WordPress-based websites that utilize the List Site Contributors plugin. Successful exploitation can lead to unauthorized disclosure of sensitive information such as session tokens or personal data, enabling attackers to impersonate users or escalate privileges. This can facilitate further attacks like phishing, defacement, or unauthorized transactions, undermining user trust and potentially violating data protection regulations such as GDPR. The reflected XSS nature means that the attack requires user interaction, but the ease of crafting malicious links and the widespread use of WordPress in Europe increase the risk. While availability is not directly impacted, the reputational damage and potential compliance penalties can be substantial. Organizations in sectors with high online engagement, including e-commerce, media, and public services, are particularly vulnerable. The absence of known exploits in the wild currently provides a window for proactive mitigation, but the medium severity score underscores the need for timely action.

1. Monitor official channels of the mallsop List Site Contributors plugin for security updates and apply patches immediately upon release. 2. Until a patch is available, implement web application firewall (WAF) rules to detect and block malicious payloads targeting the 'alpha' parameter. 3. Employ input validation and output encoding at the application level if custom modifications are possible, ensuring all user-supplied data is properly sanitized. 4. Educate users and administrators about the risks of clicking unsolicited links, especially those that appear to reference the vulnerable plugin or site. 5. Conduct regular security audits and penetration testing focused on XSS vulnerabilities within WordPress plugins. 6. Consider temporarily disabling or replacing the vulnerable plugin with a secure alternative if immediate patching is not feasible. 7. Use Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on affected websites. 8. Review and tighten user permissions and session management to limit the impact of potential session hijacking.