CVE-2026-124697 in Kendo UI
Summary
by MITRE • 11/12/2026
In Progress Kendo UI for jQuery, Chart shared-tooltip rendering treats bound category and series-name values as raw HTML. An attacker who can influence values consumed by an affected Chart can inject markup that executes as JavaScript when a user displays the shared tooltip. Successful exploitation may compromise the confidentiality and integrity of data available in the user's browser context. Version 2016.2.607 or earlier may be affected, but earlier releases have not been verified. The latest vulnerable version is 2026.3.1015; the issue is fixed in version 2026.4.1111.
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Analysis
by VulDB Data Team • 11/12/2026
The vulnerability identified in Progress Kendo UI for jQuery represents a significant client-side security flaw rooted in improper input validation and output encoding within the charting component's shared-tooltip rendering logic. Specifically, when generating tooltips that display bound category labels or series names, the library fails to sanitize these values before injecting them into the Document Object Model as raw HTML rather than plain text. This architectural oversight allows any data source feeding into the chart configuration to introduce arbitrary markup directly into the user interface without escaping special characters such as angle brackets or quotation marks. The flaw is particularly insidious because it occurs during a standard interaction pattern where users hover over chart elements, making it highly likely to be triggered in typical usage scenarios rather than requiring obscure edge cases for exploitation.
From an offensive security perspective, this vulnerability aligns closely with the Common Weakness Enumeration category CWE-79, which defines Cross-Site Scripting (XSS) involving untrusted data stored and later reflected back to a user without proper validation or encoding. The specific mechanism here is often categorized as DOM-based XSS because the malicious payload originates from client-side script processing of dynamic content rather than server-rendered HTML. Furthermore, this behavior can be mapped to MITRE ATT&CK technique T1059.007, which covers JavaScript execution within browser environments. By injecting a crafted string containing event handlers or script tags into the category or series name fields, an attacker can achieve arbitrary code execution in the context of the victim's session. This is distinct from stored XSS because the payload does not necessarily need to be persisted on a server; it only needs to exist in the data structure passed to the Kendo UI widget at runtime.
The operational impact of this vulnerability extends beyond simple defacement or alert boxes, as attackers can leverage JavaScript execution to perform session hijacking, credential theft, and unauthorized actions within the application's trusted context. Since modern web applications often rely heavily on AJAX calls and local storage for state management, an attacker exploiting this flaw could extract sensitive tokens stored in cookies or localStorage, redirect users to phishing sites, or manipulate the DOM to alter business logic displayed to other users if shared data views are involved. The confidentiality of user-specific data is compromised because the injected script runs with the same privileges as legitimate application code, allowing access to protected resources that would otherwise be inaccessible. Additionally, integrity issues arise if an attacker modifies local storage contents or alters form submissions before they are sent to the backend server.
Mitigation strategies for this vulnerability involve both immediate remediation and long-term architectural improvements. The most effective solution is to upgrade the Kendo UI library to version 2026.4.1111 or later, where the rendering engine has been patched to properly encode HTML entities in tooltip content regardless of whether they are bound from data sources. For environments unable to update immediately due to dependency constraints, developers should implement manual sanitization on all category and series name values before passing them to the chart configuration object. This involves using standard JavaScript methods like encodeURIComponent or custom regex-based filters to strip out script tags, event handlers, and other executable HTML constructs. Additionally, implementing a strict Content Security Policy (CSP) can provide an additional layer of defense by restricting the sources from which scripts are allowed to execute, thereby neutralizing many XSS payloads even if they successfully inject into the DOM. Regular security audits focusing on data binding practices in frontend frameworks are essential to prevent similar reflection vulnerabilities in other components that may share this architectural pattern.