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  3. CVE-2019-18935
Exploited in the wildUsed by ransomwareServers & business softwareWork IT

CVE-2019-18935 Progress Telerik UI for ASP.NET AJAX: unsafe data loading

In plain words: The program unpacks saved data from outside without checking it is safe. Usually lets an attacker run code on the server.

Confirmed exploited by CISA on · US federal patch deadline May 3, 2022

What to do

  1. Install Progress's security update for Telerik UI for ASP.NET AJAX. If no update exists, follow the vendor's workaround or stop using the product until one ships.
  2. Keep a list of every internet-facing server you run so nothing is forgotten.
  3. Patch anything in this catalog first, ahead of normal patch cycles.
  4. Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.

Who is affected

Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.

The details

Official name
Progress Telerik UI for ASP.NET AJAX Deserialization of Untrusted Data Vulnerability
Product
Progress Telerik UI for ASP.NET AJAX
CISA description
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.
Type of flaw
Unsafe data loading (CWE-502)
Confirmed exploited
Nov 3, 2021 — known to be used in ransomware attacks
US federal patch deadline
May 3, 2022

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Answering about CVE-2019-18935 ·

Questions about CVE-2019-18935

Is CVE-2019-18935 being exploited?

Yes. CISA added CVE-2019-18935 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks, including by ransomware groups.

How do I fix CVE-2019-18935?

Install Progress's security update for Telerik UI for ASP.NET AJAX. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.

Am I affected by CVE-2019-18935?

Only if you use Progress Telerik UI for ASP.NET AJAX. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

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