CVEs / CVE-2017-9248

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

Known exploited in the CISA KEV catalog since 3 Nov 2021
critical 9.8 CVSS 3.1 (NVD)
EPSS 75% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
Last changed at its sources 17 Jun 2026

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Summary

Progress Telerik UI for ASP.NET AJAX and Sitefinity have a cryptographic weakness in Telerik.Web.UI.dll that can be exploited to disclose encryption keys (Telerik.Web.UI.DialogParametersEncryptionKey and/or the MachineKey), perform cross-site-scripting (XSS) attacks, compromise the ASP.NET ViewState, and/or upload and download files.
CISA, Known Exploited Vulnerabilities catalog

Description

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.
The CVE record, via NVD · published 3 Jul 2017 · NVD status: Analyzed

Affected and fixed versions

As stated by the CVE record (from the CNA)
Product	Affected	Fixed in
n/a n/a	n/a	—

Exploitation

In CISA KEV since	3 Nov 2021
Due date for US federal agencies	3 May 2022
Used in ransomware campaigns	Unknown
Required action	Apply updates per vendor instructions.

Severity

CVSS 3.1	9.8 critical `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` Scored by NVD
Weakness	CWE-522

References

CVE-2017-9248 on NVD
CVE-2017-9248 in the CISA KEV catalog
http://www.securityfocus.com/bid/99965 Broken Link, Third Party Advisory, VDB Entry
http://www.telerik.com/blogs/security-alert-for-telerik-ui-for-asp.net-ajax-and-progress-sitefinity Vendor Advisory
http://www.telerik.com/support/kb/aspnet-ajax/details/cryptographic-weakness Mitigation, Vendor Advisory
https://www.exploit-db.com/exploits/43873/ Exploit, Third Party Advisory, VDB Entry
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-9248 US Government Resource

Sources

Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.

This product uses data from the NVD API but is not endorsed or certified by the NVD.