Exploited. On CISA's list since 2022-04-11.
Telerik UI for ASP.NET AJAX Unrestricted File Upload Vulnerability
CVE-2017-11317 · Telerik User Interface (UI) for ASP.NET AJAX · Published 2017-08-23
How bad would it be?
9.8 out of 10
CVSS rates it critical: about as damaging as flaws get.
How likely is it to be used?
84%
Estimated chance of exploitation in the next 30 days, among the top 1% of all scored flaws (EPSS, 2026-10-29).
Is it already being used?
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 1642 days ago (2022-05-02).
What CISA says to do
Apply updates per vendor instructions.
Telerik.Web.UI in Progress Telerik UI for ASP.NET AJAX allows remote attackers to perform arbitrary file uploads or execute arbitrary code.
What the flaw is
Telerik.Web.UI in Progress Telerik UI for ASP.NET AJAX before R1 2017 and R2 before R2 2017 SP2 uses weak RadAsyncUpload encryption, which allows remote attackers to perform arbitrary file uploads or execute arbitrary code.
From the NVD.
Fixes and advisories
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Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
CWE-326 · CISA KEV; NVD record: 134c704f-9b21-4f2e-91b3-4a467353bcc0; NVD record: nvd@nist.gov. We have not selected a close learning match for this label.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
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Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.