CVE-2017-9248
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.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- securityfocus.com/bid/99965Broken LinkThird Party Advisory
- telerik.com/blogs/security-alert-for-telerik-ui-for-asp.net-ajax-and-progress-sitefinityVendor Advisory
- telerik.com/support/kb/aspnet-ajax/details/cryptographic-weaknessMitigationVendor Advisory
- exploit-db.com/exploits/43873/ExploitThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-9248US Government Resource
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1637 days
- CVSS
- 9.8 CRITICAL
- EPSS (30-day exploit probability)
- 75.1% · top 1% of all CVEs
- Weakness
- CWE-522
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.