CVE-2017-9248: Progress Telerik UI for ASP.NET AJAX and Sitefinity Cryptographic Weakness Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 75.1% chance of exploitation in the next 30 days.

Telerik.Web.UI.dll in Progress Telerik UI for ASP.NET AJAX before R2 2017 SP1 and Sitefinity before 10.0.6412.0 does not properly protect Telerik.Web.UI.DialogParametersEncryptionKey or the MachineKey, which makes it easier for remote attackers to defeat cryptographic protection mechanisms, leading to a MachineKey leak, arbitrary file uploads or downloads, XSS, or ASP.NET ViewState compromise.

Affected products

• Progress Sitefinity: before 10.0.6412.0 (fixed in 10.0.6412.0)
• Telerik UI For ASP.NET AJAX: up to and including 2017.2.503

Published 2017-07-03. Last modified 2026-06-17.