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Known exploited · Progress

CVE-2019-18935: Progress Telerik UI for ASP.NET AJAX Deserialization of Untrusted Data Vulnerability

What it is

Progress Telerik UI for ASP.NET AJAX contains a deserialization of untrusted data vulnerability through RadAsyncUpload which leads to code execution on the server in the context of the w3wp.exe process.

Added November 3, 2021Due May 3, 2022CISA KEV catalog 2026.10.01

Vendor
Progress
Product
Telerik UI for ASP.NET AJAX
Added to KEV
November 3, 2021
CISA due date
May 3, 2022
Ransomware use
Known

What CISA requires

Apply updates per vendor instructions.

Forensic triage

No

What to do now

  1. Find every instance of Telerik UI for ASP.NET AJAX you run, including the forgotten ones, and check its version against the vendor advisory.
  2. Apply the vendor's fix or mitigation, before May 3, 2022 if you are bound by CISA's deadline, sooner if it faces the internet.
  3. Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
  4. Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops Java deserialization payloads.

References

CVE-2019-18935 in the National Vulnerability Database

The Dome

Block it at the edge while you patch

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops Java deserialization payloads before they reach your application.

See the Dome

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.