CVE-2026-14865: XXE Denial of Service via RadLayoutBuilder Client State in Telerik UI for ASP.NET AJAX

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-22 · updated 2026-10-24
Weakness: CWE-776

Description

In Progress® Telerik® UI for AJAX prior to v2026.2.708, the internal LayoutBuilder control processes client-state XML without disabling DTD processing, allowing unauthenticated denial of service via recursive XML entity expansion.

Affected products

Progress Software Telerik UI for ASP.NET AJAX: from 2009.31314 before 2026.2.708 — fixed in 2026.2.708

How to fix

Upgrade to a fixed version: Progress Software Telerik UI for ASP.NET AJAX 2026.2.708. Check the vendor advisory for mitigations.

References

https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/kb-security-rlb-xxe-injection-client-state-cve-2026-14865

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