CVE-2026-1097 in ThemeRuby Multi Authors Plugin
Summary
by MITRE • 01/24/2026
The ThemeRuby Multi Authors – Assign Multiple Writers to Posts plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'before' and 'after' shortcode attributes in all versions up to, and including, 1.0.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 01/25/2026
The vulnerability identified as CVE-2026-1097 affects the ThemeRuby Multi Authors plugin for WordPress, specifically targeting versions up to and including 1.0.0. This represents a critical security flaw that exploits the plugin's insufficient input sanitization and output escaping mechanisms within its shortcode functionality. The vulnerability manifests through the 'before' and 'after' attributes of the shortcode implementation, creating an attack surface that allows malicious actors to execute persistent cross-site scripting attacks against unsuspecting users. The flaw is particularly concerning because it requires only Contributor-level access or higher, making it accessible to users who already possess significant privileges within the WordPress environment.
The technical nature of this vulnerability aligns with CWE-79, which describes Cross-Site Scripting (XSS) flaws that occur when web applications fail to properly validate or escape user-supplied input before incorporating it into dynamically generated web pages. The plugin's failure to adequately sanitize the 'before' and 'after' shortcode parameters creates a persistent XSS vector where malicious scripts can be stored within the plugin's data handling mechanisms. When legitimate users access pages containing these injected scripts, the malicious code executes in their browsers, potentially leading to session hijacking, credential theft, or further compromise of the WordPress installation. This stored XSS vulnerability operates through the standard WordPress shortcode processing pipeline, where user input is not properly escaped before being rendered in the HTML output.
From an operational perspective, the impact of CVE-2026-1097 extends beyond simple script execution as it enables attackers to leverage the existing trust relationships within the WordPress environment. Contributors and higher-level users typically have access to sensitive content and administrative functions, making this vulnerability particularly dangerous when attackers can manipulate the output of the multi-authors plugin to target other users within the same installation. The attack requires minimal sophistication since the vulnerability exists within legitimate plugin functionality, and the injected scripts can be crafted to perform various malicious activities including redirecting users to phishing sites, stealing cookies, or even executing additional exploits against the WordPress environment. This makes the vulnerability particularly attractive to threat actors seeking to establish persistent access or conduct broader attacks against WordPress installations.
The attack vector for this vulnerability follows the patterns outlined in the MITRE ATT&CK framework under the T1190 technique for Exploit Public-Facing Application, where attackers target web applications to execute malicious code on victim systems. The exploitation process involves an authenticated attacker creating posts with malicious scripts in the affected shortcode attributes, which then persist in the database and execute whenever the page content is rendered. Organizations should immediately implement mitigations including updating to the latest version of the plugin if available, implementing proper input validation at the application level, and considering the principle of least privilege to limit the impact of compromised accounts. Additionally, network-based detection measures such as web application firewalls and intrusion detection systems should be configured to monitor for suspicious shortcode parameter usage patterns. The vulnerability underscores the importance of proper input sanitization and output escaping practices as recommended in OWASP Top Ten security guidelines, particularly in the context of content management systems where user-generated content processing is common.