CVE-2026-1097 identifies a stored Cross-Site Scripting (XSS) vulnerability in the ThemeRuby Multi Authors – Assign Multiple Writers to Posts plugin for WordPress, present in all versions up to and including 1.0.0. The vulnerability arises from improper neutralization of input during web page generation, specifically insufficient sanitization and output escaping of the 'before' and 'after' shortcode attributes. Authenticated attackers with Contributor-level access or higher can inject arbitrary JavaScript code into posts or pages via these shortcode attributes. Because the injected scripts are stored persistently, they execute in the context of any user who views the affected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions on behalf of users. The vulnerability does not require user interaction beyond viewing the page and has a CVSS 3.1 base score of 6.4, reflecting medium severity with network attack vector, low attack complexity, and privileges required. The scope is changed (S:C) because the vulnerability affects resources beyond the attacker’s privileges, impacting other users. No public exploits are currently known, but the risk remains significant due to the common use of WordPress and the plugin’s functionality in multi-author environments. The vulnerability was published on January 24, 2026, with no patches currently available, highlighting the need for immediate mitigation steps. The CWE-79 classification confirms this is a classic stored XSS issue, a well-understood and dangerous web vulnerability.

For European organizations, this vulnerability poses a risk to websites using the ThemeRuby Multi Authors plugin, particularly those with multiple contributors such as news agencies, educational institutions, and corporate blogs. Exploitation can lead to session hijacking, unauthorized actions performed under legitimate user credentials, defacement, or distribution of malware through injected scripts. This undermines the confidentiality and integrity of user data and can damage organizational reputation. Since the attack vector is network-based and requires only contributor-level access, insider threats or compromised contributor accounts can be leveraged to exploit the vulnerability. The scope change means that even users with higher privileges or site visitors can be affected, broadening the impact. Given the widespread use of WordPress in Europe and the plugin’s role in managing multiple authors, the vulnerability could facilitate targeted attacks against organizations relying on collaborative content publishing. Additionally, regulatory frameworks such as GDPR impose strict requirements on protecting user data, and exploitation could lead to compliance violations and financial penalties.

Immediate mitigation should focus on restricting contributor-level permissions to trusted users only, minimizing the risk of malicious shortcode attribute injection. Organizations should monitor and audit contributor activities for suspicious shortcode usage. Deploying a Web Application Firewall (WAF) with robust XSS filtering rules can help detect and block malicious payloads targeting the vulnerable shortcode attributes. Until an official patch is released, consider disabling or removing the ThemeRuby Multi Authors plugin if feasible, or replacing it with alternative multi-author management plugins that have been verified as secure. Implement Content Security Policy (CSP) headers to restrict script execution sources, limiting the impact of injected scripts. Regularly update WordPress core and all plugins to the latest versions to reduce exposure to known vulnerabilities. Conduct security awareness training for contributors to recognize the risks of injecting untrusted content. Finally, monitor security advisories from the plugin vendor and WordPress community for patch releases and apply them promptly.