CVE-2026-40806 in Blog Posts and Category Filter Plugin
Summary
by MITRE • 10/06/2026
Unauthenticated Cross Site Scripting (XSS) in Blog, Posts and Category Filter for Elementor <= 2.1.0 versions.
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Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified as an unauthenticated cross-site scripting flaw within the Elementor plugin prior to version 2.1.0 represents a significant security risk affecting WordPress-based websites that utilize this popular page builder framework. The core of the issue lies in insufficient input validation and output encoding mechanisms applied specifically when processing user-supplied data through the Blog, Posts, and Category Filter widgets. These components are designed to dynamically display content based on selected categories or post types, but they fail to adequately sanitize inputs before rendering them within the HTML context of a web page. This oversight allows an attacker to inject malicious JavaScript code into the application's response stream without requiring any form of authentication or prior login credentials.
From a technical perspective, this vulnerability is classified under CWE-79, which denotes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. The flaw typically manifests when user-controlled parameters are reflected directly back to the browser in an unsafe manner. In the context of Elementor's filter widgets, if a malicious actor can manipulate query strings or form inputs associated with category filtering, they can embed script tags or event handlers that execute within the victim's browser session. Because this execution occurs without authentication barriers, it is classified as non-persistent or reflected XSS depending on whether the payload is stored in server-side state or merely passed via URL parameters and immediately rendered. The lack of proper encoding means special characters such as angle brackets are not converted to their HTML entity equivalents, allowing the browser's parser to interpret injected strings as executable code rather than plain text data.
The operational impact of this vulnerability extends beyond simple script execution. An attacker leveraging this flaw can perform a variety of malicious actions against users who visit vulnerable pages containing the compromised widget content. These actions include stealing session cookies or authentication tokens, which could lead to account takeover if those sessions grant administrative privileges. Furthermore, attackers may redirect victims to phishing sites designed to harvest credentials for other services, deface website appearances by altering DOM elements, or deploy malware downloads through drive-by techniques. Since Elementor is widely used across thousands of websites globally, the potential blast radius is substantial, affecting not only site administrators but also end-users who interact with affected pages under the assumption that they are secure and trustworthy environments provided by legitimate content creators.
This vulnerability aligns closely with MITRE ATT&CK technique T1059, specifically sub-technique 007 for JavaScript-based command execution or browser-side scripting abuse. It exemplifies how web application frameworks can inadvertently introduce attack surfaces through complex widget systems that handle dynamic data rendering. The absence of robust sanitization libraries in earlier versions highlights a common pitfall where convenience and ease-of-use are prioritized over security hardening during development cycles. Attackers often exploit such weaknesses using automated scanning tools or targeted manual testing to identify sites running outdated plugin versions, making this a high-value target for opportunistic cybercriminals seeking low-effort entry points into otherwise secure infrastructure.
To mitigate the risks associated with this vulnerability, immediate action is required by website administrators and developers utilizing Elementor. The primary remediation step involves upgrading the Elementor plugin to version 2.1.0 or later, where these input validation flaws have been addressed through improved sanitization routines and stricter output encoding practices. For organizations unable to upgrade immediately due to compatibility constraints with other plugins or themes, implementing a Web Application Firewall (WAF) can provide temporary protection by filtering out malicious payloads containing script tags or suspicious JavaScript patterns before they reach the application layer. Additionally, enabling Content Security Policy headers can help mitigate the impact of successful XSS attacks by restricting the sources from which scripts are allowed to execute, thereby reducing the effectiveness of injected code even if it bypasses initial validation checks. Regular security audits and dependency management practices should be adopted to ensure that third-party components remain patched against known vulnerabilities in a timely manner.