CVE-2026-1099 identifies a stored Cross-Site Scripting (XSS) vulnerability in the 'Administrative Shortcodes' WordPress plugin developed by shazdeh. This vulnerability arises from improper neutralization of input during web page generation (CWE-79), specifically in the handling of 'login' and 'logout' shortcode attributes. The plugin fails to adequately sanitize and escape these inputs, allowing authenticated users with Contributor-level access or higher to inject arbitrary JavaScript code into pages. Because the malicious script is stored, it executes every time the infected page is loaded by any user, potentially compromising session tokens, redirecting users, or performing actions on behalf of users without their consent. The vulnerability affects all versions up to and including 0.3.4. The CVSS 3.1 base score is 6.4, reflecting network attack vector, low attack complexity, requiring privileges (Contributor or above), no user interaction, and impacts confidentiality and integrity with a scope change. No patches or known exploits are currently available, but the vulnerability is publicly disclosed. The flaw is critical in multi-user WordPress environments where contributors can add or edit content, as it enables privilege escalation and persistent client-side attacks.

For European organizations, this vulnerability poses a significant risk to WordPress-based websites that utilize the Administrative Shortcodes plugin, especially those with multi-user content management workflows. Exploitation can lead to session hijacking, unauthorized actions performed on behalf of users, data theft, and defacement. Confidentiality and integrity of user data and site content can be compromised. Organizations in sectors such as government, education, media, and e-commerce that rely on WordPress for public-facing or internal portals are particularly vulnerable. The persistent nature of stored XSS increases the attack surface, potentially affecting all visitors or logged-in users accessing the compromised pages. This can damage organizational reputation, lead to regulatory non-compliance (e.g., GDPR breaches due to data exposure), and disrupt business operations. The requirement for contributor-level access limits the attack vector but insider threats or compromised contributor accounts can facilitate exploitation.

1. Monitor the plugin vendor’s official channels for a security patch and apply updates immediately upon release. 2. Until a patch is available, restrict Contributor-level access to trusted users only and audit existing contributor accounts for suspicious activity. 3. Implement Web Application Firewall (WAF) rules to detect and block malicious script injections targeting shortcode attributes. 4. Use security plugins that enforce input sanitization and output escaping on WordPress sites. 5. Conduct regular security reviews and penetration testing focusing on user input handling in WordPress plugins. 6. Educate content contributors about the risks of injecting untrusted content and enforce strict content policies. 7. Consider disabling or replacing the Administrative Shortcodes plugin if it is not essential. 8. Employ Content Security Policy (CSP) headers to limit the impact of injected scripts. 9. Monitor logs for unusual activity related to shortcode usage or page edits. 10. Backup site data regularly to enable quick recovery if exploitation occurs.