CVE-2026-1127 is a reflected Cross-Site Scripting (XSS) vulnerability identified in the Timeline Event History plugin for WordPress, developed by wpdiscover. This vulnerability affects all versions up to and including 3.2. The root cause is insufficient input sanitization and output escaping of the 'id' parameter used during web page generation. An attacker can craft a malicious URL containing a script payload in the 'id' parameter, which, when clicked by an unsuspecting user, causes the injected script to execute in the context of the victim's browser. This can lead to theft of cookies, session tokens, or other sensitive information, as well as unauthorized actions performed on behalf of the user. The vulnerability is exploitable remotely over the network without requiring authentication, but it does require user interaction (clicking a malicious link). The CVSS v3.1 score is 6.1, indicating medium severity, with the vector indicating network attack vector, low attack complexity, no privileges required, user interaction required, and impact on confidentiality and integrity but not availability. No patches or fixes are currently linked, and no known exploits have been reported in the wild as of the publication date. The vulnerability falls under CWE-79, which is a common web application security weakness related to improper neutralization of input during web page generation.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on WordPress sites with the Timeline Event History plugin installed. Exploitation can lead to unauthorized disclosure of sensitive information such as session cookies, enabling attackers to hijack user sessions and impersonate legitimate users. This can result in data breaches, unauthorized changes to website content, or further exploitation of user accounts. The integrity of data displayed or processed by the affected plugin can be compromised, potentially damaging organizational reputation and trust. Although availability is not directly impacted, the indirect consequences of successful attacks, such as defacement or phishing, can disrupt business operations and customer confidence. Organizations in sectors with strict data protection regulations, such as finance, healthcare, and e-commerce, face increased compliance risks if such vulnerabilities are exploited. The requirement for user interaction means targeted phishing campaigns could be used to exploit this vulnerability, increasing the risk to employees and customers.

1. Monitor for official patches or updates from wpdiscover and apply them immediately once available to remediate the vulnerability. 2. Until patches are released, implement strict input validation and output encoding on the 'id' parameter at the web application or server level to neutralize malicious scripts. 3. Deploy a Web Application Firewall (WAF) with robust XSS detection and prevention rules to block malicious payloads targeting this vulnerability. 4. Conduct user awareness training focused on recognizing and avoiding suspicious links, especially those that could trigger reflected XSS attacks. 5. Review and limit the use of the Timeline Event History plugin if it is not essential, or consider alternative plugins with better security track records. 6. Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 7. Regularly audit and monitor web server logs for unusual requests containing suspicious parameters indicative of attempted exploitation. 8. Employ multi-factor authentication (MFA) to reduce the impact of session hijacking if credentials are compromised.