CVE-2017-9248: in the CISA KEV catalogue

Progress Telerik UI for ASP.NET AJAX and Sitefinity Cryptographic Weakness Vulnerability. CISA added CVE-2017-9248 to the Known Exploited Vulnerabilities catalogue on 2021-11-03 with a default due date of 2022-05-03. Known ransomware campaign use: Unknown. Forensic triage flag: No.

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 description)

Vendor / product: Progress ASP.NET AJAX and Sitefinity
CWE: CWE-522
CISA required action: Apply updates per vendor instructions.
EPSS: 75%, percentile 99 (scored 2026-11-03)

EPSS puts about 75 in 100 odds (75%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 99% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.

Vendor and reference links (from CISA)

https://nvd.nist.gov/vuln/detail/CVE-2017-9248

Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.

Data dates. CISA KEV catalogue version 2026.11.03, released 2026-11-03, 1,767 entries (checked 2026-11-03). EPSS model v2026.06.15, scored 2026-11-03, 399,388 CVEs. Sources: CISA and FIRST (EPSS by FIRST; scores generated by Empirical Security). Copied to our own database and refreshed automatically; if a refresh fails, the previous copy keeps serving with its own date.

Frequently asked questions

Is CVE-2017-9248 in the CISA KEV catalogue?

Yes. CISA added CVE-2017-9248 (Progress Telerik UI for ASP.NET AJAX and Sitefinity Cryptographic Weakness Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2021-11-03. CISA's default due date for it is 2022-05-03.

Is CVE-2017-9248 used in ransomware attacks?

CISA marks known ransomware campaign use as Unknown for CVE-2017-9248. That means CISA lacks confirmation, not that ransomware groups do not use it.

What should I do about CVE-2017-9248?

CISA's required action: Apply updates per vendor instructions.

Sources

CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
NVD record for CVE-2017-9248