CVE-2026-13185 in Telerik UI for ASP.NET AJAX
Summary
by MITRE • 07/22/2026
In Progress® Telerik® UI for AJAX prior to v2026.2.708, applications using cookie-based storage in RadPersistenceManager or RadDockLayout deserialize attacker-controlled cookie content, allowing unauthenticated remote code execution.
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Analysis
by VulDB Data Team • 07/22/2026
The vulnerability exists within In Progress Telerik UI for AJAX versions prior to v2026.2.708 where the RadPersistenceManager and RadDockLayout components utilize cookie-based storage mechanisms that fail to properly validate or sanitize deserialization inputs. This flaw stems from insufficient input validation during the cookie deserialization process, allowing remote attackers to craft malicious cookie content that when processed by the application's persistence manager, triggers arbitrary code execution without requiring authentication credentials.
The technical implementation of this vulnerability leverages the .NET serialization framework's deserialization capabilities within the Telerik UI components. When applications store user interface state information using RadPersistenceManager or manage layout configurations through RadDockLayout, these components rely on cookie storage to maintain session data across requests. The flaw occurs because the deserialization process does not perform adequate security checks to prevent malicious object reconstruction from attacker-controlled cookie data.
This vulnerability directly maps to CWE-502 which addresses Deserialization of Untrusted Data, a critical weakness that enables attackers to execute arbitrary code through maliciously crafted serialized objects. The attack vector requires an unauthenticated remote attacker who can manipulate cookie values sent to the vulnerable application, making it particularly dangerous as it bypasses traditional authentication mechanisms.
The operational impact of this vulnerability is severe and potentially catastrophic for affected applications. Successful exploitation allows attackers to execute arbitrary commands on the target server with the privileges of the web application process, potentially leading to complete system compromise. Attackers can leverage this vulnerability to establish persistent backdoors, exfiltrate sensitive data, or deploy additional malicious payloads within the compromised environment.
Mitigation strategies should focus on immediate patching of affected Telerik UI for AJAX components to version v2026.2.708 or later where the deserialization vulnerabilities have been addressed. Organizations should also implement cookie validation mechanisms that sanitize and verify all serialized data before deserialization occurs, particularly for any custom implementations that utilize similar patterns. Network-level protections including web application firewalls can help detect and block suspicious cookie content patterns, while security monitoring should be enhanced to identify anomalous deserialization activities in application logs. The vulnerability demonstrates the critical importance of proper input validation and secure serialization practices within web applications, aligning with ATT&CK technique T1548.003 for Abuse of Functionality and T1210 for Exploitation of Remote Services.