CVE-2026-13181 in Telerik UI for ASP.NET AJAX
Summary
by MITRE • 07/22/2026
In Progress® Telerik® UI for AJAX prior to v2026.2.708, forged upload metadata can influence AsyncUploadTypeName processing and trigger unsafe attacker-controlled type resolution, enabling remote code execution in affected deployments.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 07/22/2026
The vulnerability in In Progress® Telerik® UI for AJAX versions prior to v2026.2.708 represents a critical security flaw that exploits the asynchronous file upload functionality to achieve remote code execution. This issue stems from insufficient validation of upload metadata, specifically affecting the AsyncUploadTypeName parameter processing within the framework's file handling mechanisms. The vulnerability allows attackers to manipulate metadata values that are subsequently used for type resolution during file upload operations, creating a pathway for arbitrary code execution on affected systems.
The technical implementation of this flaw involves the manipulation of metadata fields that control how uploaded files are processed and interpreted by the application. When the AsyncUploadTypeName parameter is improperly validated or sanitized, attackers can inject malicious type information that bypasses normal security checks. This vulnerability operates at the intersection of insecure deserialization and type confusion patterns, where attacker-controlled data influences the runtime type resolution process. The flaw essentially creates a scenario where the application's type system becomes vulnerable to manipulation through crafted upload metadata, enabling attackers to execute arbitrary code with the privileges of the affected application.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables comprehensive remote code execution capabilities within the target environment. Attackers can leverage this flaw to upload malicious files that are then processed by the vulnerable framework, potentially leading to full system compromise. The vulnerability affects deployments where Telerik UI for AJAX is used for file upload functionality, particularly in web applications that handle user-uploaded content without proper input validation. This creates a significant risk for organizations running affected versions, as the exploitation requires minimal privileges and can be performed through standard web-based attack vectors.
Security mitigations for this vulnerability should focus on immediate version upgrades to v2026.2.708 or later, which contain patches addressing the metadata validation issues. Organizations should also implement additional defensive measures including input validation for upload parameters, strict content type checking, and monitoring of unusual file upload patterns. The vulnerability aligns with CWE-20 Improper Input Validation and CWE-457 Use of Uninitialized Variable, while its exploitation pattern corresponds to ATT&CK technique T1190 Exploit Public-Facing Application and T1059 Command and Scripting Interpreter. Network segmentation and application firewalls can provide additional layers of protection, though the most effective defense remains proper patch management and adherence to security best practices for file upload handling.