Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function. This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. Exploitation can result in remote code execution. (As of 2020.1.114, a default setting prevents the exploit. In 2019.3.1023, but not earlier versions, a non-default setting can prevent exploitation.)
https://services.google.com/fh/files/misc/m-trends-2024.pdf
https://www.tenable.com/cyber-exposure/a-look-inside-the-ransomware-ecosystem
https://www.cisa.gov/news-events/cybersecurity-advisories/aa22-117a
https://www.cisa.gov/news-events/cybersecurity-advisories/aa21-209a
https://www.cybereason.com/blog/research/cybereason-vs.-netwalker-ransomware
https://www.telerik.com/support/whats-new/release-history
https://www.telerik.com/support/kb/aspnet-ajax/details/allows-javascriptserializer-deserialization
https://github.com/noperator/CVE-2019-18935
https://codewhitesec.blogspot.com/2019/02/telerik-revisited.html
http://packetstormsecurity.com/files/155720/Telerik-UI-Remote-Code-Execution.html