CVE-2026-3997 in Text Toggle Plugin
Summary
by MITRE • 03/21/2026
The Text Toggle plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'title' shortcode attribute of the [tt_part] and [tt] shortcodes in all versions up to and including 1.1. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes. Specifically, in the avp_texttoggle_part_shortcode() function, the 'title' attribute is extracted from shortcode attributes and concatenated directly into HTML output without any escaping — both within an HTML attribute context (title="...") on line 116 and in HTML content on line 119. While the 'class' attribute is properly validated using ctype_alnum(), the 'title' attribute has no sanitization whatsoever. An attacker can inject double-quote characters to break out of the title attribute and inject arbitrary HTML attributes including event handlers. 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 • 03/21/2026
The vulnerability identified as CVE-2026-3997 affects the Text Toggle plugin for WordPress, specifically targeting versions through 1.1. This represents a critical stored cross-site scripting flaw that undermines the security integrity of WordPress installations. The issue manifests within the avp_texttoggle_part_shortcode() function where user-supplied input is processed without adequate sanitization measures. The vulnerability stems from insufficient validation of the 'title' shortcode attribute in both [tt_part] and [tt] shortcodes, creating an exploitable entry point for malicious actors to inject harmful scripts into the affected system.
The technical implementation of this vulnerability occurs through improper handling of user-provided data within the plugin's shortcode processing mechanism. When the 'title' attribute is extracted from shortcode parameters on line 116, it is directly embedded into HTML output within an attribute context using title=". This unescaped insertion allows attackers to inject double quotes and break out of the attribute boundary. The same flaw exists on line 119 where the title is inserted into HTML content without proper escaping. While the plugin does implement ctype_alnum() validation for the 'class' attribute, the 'title' attribute receives no sanitization whatsoever, creating a significant security gap that attackers can exploit to inject arbitrary HTML and JavaScript code.
The operational impact of this vulnerability is substantial, particularly for WordPress environments where contributors and above have access to the system. Authenticated attackers with contributor-level privileges can leverage this flaw to inject malicious scripts that will execute whenever any user accesses a page containing the injected content. This creates a persistent threat vector where compromised pages can serve as attack vectors for further exploitation, potentially leading to account takeovers, data exfiltration, or the deployment of additional malware. The stored nature of this XSS vulnerability means that once injected, malicious code remains persistent until manually removed, making it particularly dangerous for administrators who may not immediately detect the compromise.
Security mitigation strategies for this vulnerability should prioritize immediate plugin updates to versions that address the sanitization flaws. Administrators should implement strict input validation for all user-supplied shortcode attributes and ensure proper output escaping before rendering any user-provided content. The fix should incorporate context-appropriate escaping mechanisms such as wp_kses() for HTML content and esc_attr() for attribute contexts. Additionally, implementing a content security policy that restricts script execution and monitoring for unauthorized shortcode modifications can provide additional defense layers. This vulnerability aligns with CWE-79 (Cross-site Scripting) and represents a clear violation of secure coding practices outlined in the OWASP Top Ten, specifically addressing the risk of unauthorized code execution in web applications. The ATT&CK framework categorizes this as a privilege escalation technique through web application vulnerabilities, where initial access is gained through contributor-level permissions to achieve persistent malicious execution within the target environment.