CVE-2026-1922 in The Events Calendar Shortcode & Block Plugin
Summary
by MITRE • 02/10/2026
The The Events Calendar Shortcode & Block plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's `ecs-list-events` shortcode `message` attribute in all versions up to, and including, 3.1.2 due to insufficient input sanitization and output escaping on user supplied attributes. 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 • 02/10/2026
The vulnerability identified as CVE-2026-1922 affects the Events Calendar Shortcode & Block plugin for WordPress, specifically targeting the `ecs-list-events` shortcode implementation. This issue represents a critical security flaw that allows authenticated attackers with contributor-level privileges or higher to execute stored cross-site scripting attacks within the WordPress environment. The vulnerability manifests through the `message` attribute of the shortcode, where insufficient input sanitization and output escaping mechanisms fail to properly validate or encode user-supplied data before processing.
The technical flaw stems from inadequate validation of the `message` attribute parameter within the plugin's shortcode handling mechanism. When administrators or contributors insert the `ecs-list-events` shortcode with a malicious `message` attribute value, the plugin fails to sanitize this input before storing it in the WordPress database. This stored data is then subsequently rendered in web pages without proper output escaping, creating an environment where malicious scripts can be executed whenever any user accesses pages containing the compromised shortcode. The vulnerability specifically affects all versions of the plugin up to and including version 3.1.2, indicating that the security flaw has existed for multiple releases and has not been adequately addressed in the patch history.
From an operational impact perspective, this vulnerability enables attackers to perform persistent XSS attacks that can compromise user sessions and potentially escalate privileges within the WordPress environment. Since the attack requires only contributor-level access, it represents a significant risk to WordPress sites where multiple users have varying permission levels. The stored nature of the vulnerability means that malicious scripts remain active until manually removed from the database, potentially affecting all users who access pages containing the compromised shortcode. This makes the vulnerability particularly dangerous in collaborative environments where multiple contributors regularly update content, as it allows attackers to establish persistent footholds within the system.
The vulnerability aligns with CWE-79 which specifically addresses Cross-Site Scripting flaws, and demonstrates characteristics consistent with ATT&CK technique T1566.001 related to spearphishing attachments. The security implications extend beyond simple script execution as attackers could potentially harvest user credentials, redirect users to malicious sites, or use the compromised environment as a launchpad for further attacks within the network. Organizations using this plugin should consider implementing immediate mitigations including plugin updates, input validation hardening, and monitoring for unauthorized shortcode modifications. The vulnerability also highlights the importance of proper security testing practices during plugin development and the necessity of implementing robust input sanitization and output escaping mechanisms to prevent such persistent XSS vulnerabilities from being introduced into content management systems.
This vulnerability represents a significant risk to WordPress installations and underscores the critical importance of maintaining up-to-date security practices. The fact that it affects a widely-used events calendar plugin means that numerous websites across various industries could be potentially compromised. Organizations should prioritize patching this vulnerability immediately and implement additional security measures including regular security audits, monitoring for suspicious shortcode usage, and implementing web application firewalls to detect and prevent similar attacks. The attack vector's reliance on contributor-level access also emphasizes the need for proper role-based access controls and user permission management within WordPress environments to minimize potential damage from compromised accounts.