CVE-2026-124696 in Kendo UI for jQuery
Summary
by MITRE • 11/12/2026
In Progress Kendo UI for jQuery, Spreadsheet sheet names are inserted into the SheetsBar menu button's data-sheet-name attribute without encoding. An attacker who can influence a sheet name can inject an event-handler attribute and execute JavaScript when a user hovers over the menu button. Successful exploitation may compromise the confidentiality and integrity of data available in the user's browser context. The first affected version is 2024.4.1112; 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 classic Cross-Site Scripting (XSS) flaw rooted in improper input validation and output encoding within the Spreadsheet component's user interface elements. Specifically, when rendering the SheetsBar menu button, the application directly inserts the name of the spreadsheet sheet into the data-sheet-name attribute without applying any form of HTML entity encoding or sanitization. This architectural oversight allows an attacker who possesses the ability to influence or control the naming convention of a worksheet to inject malicious JavaScript code fragments directly into the DOM structure. The vulnerability is present in versions ranging from 2024.4.1112 through 2026.3.1015, with remediation provided starting in version 2026.4.1111 where proper encoding mechanisms have been implemented to neutralize such injection attempts.
From a technical perspective, the exploitation vector relies on the browser's default behavior of interpreting attribute values as potential event handlers when specific patterns are detected within HTML attributes. By injecting an event-handler attribute, such as onmouseover or onclick, into the data-sheet-name field, the attacker ensures that any user interaction with the menu button triggers the execution of the injected script. The trigger condition is specifically tied to hovering over the menu button, which means exploitation does not require a click but merely visual engagement with the interface element containing the malicious sheet name. This lowers the barrier for successful exploitation and increases the likelihood of impact in environments where users frequently interact with spreadsheet navigation elements.
The operational impact of this vulnerability extends beyond simple script execution to significant compromises in data confidentiality and integrity within the user's browser context. Once the JavaScript is executed, it operates under the same origin policy as the legitimate application, granting the attacker full access to cookies, local storage, session tokens, and other sensitive data stored by the web page. An adversary can utilize this access to perform actions on behalf of the victim, such as exfiltrating confidential spreadsheet contents, modifying data integrity through unauthorized API calls, or hijacking active sessions. This effectively transforms a UI rendering flaw into a critical security breach that undermines trust in the application's ability to protect user information and maintain operational continuity.
This vulnerability aligns with CWE-79, which classifies improper neutralization of input during web page generation as a common cause of cross-site scripting attacks. Furthermore, it maps directly to MITRE ATT&CK technique T1059.007, specifically JavaScript execution within the context of client-side applications. The attack scenario also reflects aspects of CWE-83 regarding injection flaws where untrusted data is sent to an interpreter without proper validation. Understanding these mappings helps security teams contextualize the risk within broader threat landscapes and prioritize remediation efforts based on standardized vulnerability classification frameworks rather than isolated incident reports.
To mitigate this issue, organizations must immediately upgrade their Progress Kendo UI for jQuery libraries to version 2026.4.1111 or later, which includes the necessary fixes for encoding sheet names before they are rendered in the DOM. For environments where an immediate upgrade is not feasible due to dependency constraints or testing requirements, a temporary workaround involves implementing server-side validation and output encoding for any user-supplied input that becomes part of UI attribute values. Developers should ensure that all dynamic content inserted into HTML attributes is strictly encoded using appropriate context-specific escaping rules, such as HTML entity encoding for attribute contexts. Additionally, deploying Content Security Policy (CSP) headers can provide an additional layer of defense by restricting the sources from which scripts are allowed to execute, thereby mitigating the impact even if a successful injection occurs. Regular security audits and static code analysis focused on DOM-based XSS patterns should be integrated into the development lifecycle to prevent similar vulnerabilities in future releases.