CVE-2026-119369 in The Events Calendar Plugin
Summary
by MITRE • 10/30/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Liquid Web / StellarWP The Events Calendar the-events-calendar allows Stored XSS.This issue affects The Events Calendar: from n/a through 6.18.2.
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Analysis
by VulDB Data Team • 10/30/2026
The identified security flaw represents a classic instance of Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. Specifically, this vulnerability manifests as a Stored XSS within the The Events Calendar plugin for WordPress, developed by StellarWP and distributed through Liquid Web environments. Unlike reflected XSS attacks where malicious scripts are executed immediately upon user interaction with a crafted link, stored vulnerabilities persist on the target server. In this context, an attacker can inject malicious JavaScript code into data fields that are subsequently saved to the application's database. When other users or administrators view these compromised events in their web browsers, the browser interprets and executes the embedded script as part of the legitimate page content. This persistence mechanism significantly amplifies the severity of the vulnerability because a single successful injection can impact multiple victims without requiring further interaction from the attacker beyond the initial payload submission.
The technical root cause lies in insufficient input validation and output encoding mechanisms within versions 6.18.2 and earlier of The Events Calendar. When user-supplied data, such as event titles, descriptions, or custom fields, is processed by the application, it fails to adequately sanitize special characters that have meaning in HTML contexts, such as angle brackets, quotation marks, and ampersands. Consequently, when this untrusted input is rendered back into the DOM for display purposes, the browser parses the injected script tags rather than treating them as plain text data. This failure allows arbitrary JavaScript execution within the security context of the website's domain. Because The Events Calendar often handles sensitive administrative functions or displays content to a broad audience depending on site configuration, this flaw provides a direct pathway for session hijacking, credential theft via keyloggers, defacement of web pages, and redirection of users to malicious external sites designed for phishing attacks.
From an operational perspective, the impact of this vulnerability extends beyond simple script execution. Attackers can leverage stored XSS to bypass Content Security Policy directives if those policies are not strictly configured with appropriate nonce or hash values that cannot be manipulated by client-side scripts. Furthermore, since WordPress plugins often have elevated privileges depending on their role and configuration, an attacker might exploit the session of a logged-in administrator who views the compromised event data. This could lead to full compromise of the underlying WordPress installation, allowing for further lateral movement within the network infrastructure hosting the web application. The persistence of the payload means that even after the initial attack vector is discovered, the malicious code remains active until manually removed from the database or the plugin is updated and existing records are sanitized, posing a long-term risk to data integrity and user trust.
Industry standards categorize this flaw under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'). More specifically, it aligns with CWE-83 in cases where the injection occurs via stored mechanisms rather than direct request parameters. In terms of offensive security frameworks, this vulnerability maps to MITRE ATT&CK technique T1059: Command and Scripting Interpreter, particularly sub-techniques involving JavaScript execution within a browser environment. It also relates to T1189: Drive-by Client-side Execution, as the payload executes automatically upon page load for any viewer with access rights. Understanding these mappings helps security teams prioritize remediation efforts based on established threat models and common attack patterns observed in web application exploitation campaigns.
To mitigate this vulnerability, immediate action is required by updating The Events Calendar to version 6.18.3 or later, where the input validation and output encoding logic has been corrected to properly escape user-supplied data before rendering it into HTML contexts. Administrators should also implement a Web Application Firewall configured with rulesets capable of detecting and blocking common XSS payloads in POST requests associated with event creation or modification endpoints. Additionally, enforcing strict Content Security Policy headers can limit the impact if an injection does occur by restricting script execution to trusted sources only. Regular security audits focusing on input handling across all user-facing forms are recommended to prevent similar flaws from being introduced during future development cycles. Ensuring that developers adhere to secure coding practices such as context-aware encoding and parameterized queries will further reduce the attack surface for cross-site scripting vulnerabilities in WordPress ecosystems.