CVE-2026-86612 in Ninja Tables Plugin
Summary
by MITRE • 09/23/2026
The Ninja Tables WordPress plugin before 5.2.17 does not restrict shortcode expansion to administrator-authored table rows which, in a non-default configuration, allows unauthenticated users to have arbitrary shortcodes executed on a public page, and to permanently break that page, by submitting an ordinary form entry.
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Analysis
by VulDB Data Team • 09/23/2026
The vulnerability identified in Ninja Tables WordPress plugin versions prior to 5.2.17 represents a critical failure in input validation and access control mechanisms within the shortcode processing engine. This flaw specifically targets the functionality that allows users to generate dynamic tables via shortcodes, which is a common feature for displaying data-driven content on public-facing websites. The core technical issue stems from an insufficient restriction on who can author or modify table rows containing executable code snippets. In many WordPress configurations, particularly those utilizing front-end submission forms, there exists a distinction between administrative users and standard contributors or subscribers. However, the plugin fails to enforce this boundary when processing shortcodes embedded within user-submitted content. Consequently, any unauthenticated visitor or low-privilege user can inject malicious shortcode payloads into form submissions that are then rendered on public pages without adequate sanitization checks.
From a technical perspective, this vulnerability exploits the way WordPress parses and executes shortcodes during page rendering. When a user submits an ordinary HTML form containing specific text patterns recognized as shortcodes by Ninja Tables, the plugin processes these inputs directly rather than stripping or escaping them if they originate from non-administrative sources. This behavior violates the principle of least privilege, allowing attackers to execute arbitrary code within the context of the WordPress application. The impact is twofold: first, it enables Cross-Site Scripting (XSS) attacks where malicious scripts can be injected into pages viewed by other users; second, and more severely in this specific instance, it allows for persistent denial-of-service conditions. By submitting carefully crafted form entries containing malformed or recursive shortcodes, an attacker can cause the page rendering process to fail permanently, effectively breaking the affected public page until manual intervention occurs at the database level.
The operational impact of this vulnerability is significant because it affects unauthenticated users, meaning no prior login or authentication credentials are required to exploit it. This lowers the barrier for entry significantly compared to authenticated vulnerabilities. Attackers can target high-traffic pages that rely on user-generated content, such as comment sections, review platforms, or community forums built with Ninja Tables. The ability to permanently break a page disrupts business continuity and damages site integrity. Furthermore, if the executed shortcodes allow for data exfiltration or session hijacking through XSS vectors, sensitive information belonging to legitimate users could be compromised. This aligns closely with CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting, and CWE-269 regarding Improvement Control Errors where the system fails to properly restrict access for unauthorized actors.
In terms of threat modeling, this vulnerability maps directly to MITRE ATT&CK technique T1059 Command and Scripting Interpreter, specifically through web browser scripts or HTML markup injection. The attack vector is classified as Network-based with low complexity due to the reliance on standard HTTP form submissions rather than complex exploitation chains. Defenders should immediately update the Ninja Tables plugin to version 5.2.17 or later where these access controls have been hardened. For sites that cannot be updated instantly, implementing a Web Application Firewall (WAF) rule to block suspicious shortcode patterns in POST requests can provide temporary mitigation. Additionally, developers should review any custom code interacting with Ninja Tables APIs to ensure strict role-based checks are enforced before processing user input for table generation. Regular security audits focusing on front-end submission forms and shortcodes are recommended to prevent similar logic flaws in other plugins or custom themes that may share this architectural pattern.