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

Source: https://junglewise.ai/threats/cve-2019-18935-progress-telerik-ui-for-asp-net-ajax-deserialization-of-untrusted  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-11-03. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2019-18935 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2021-11-03

Progress Telerik UI for ASP.NET AJAX contains a .NET deserialization vulnerability in the RadAsyncUpload function. When encryption keys are known, an unauthenticated attacker can achieve remote code execution on the server.

Technologies: [Progress Telerik Ui For Asp.Net Ajax](https://junglewise.ai/threats/technologies/telerik-ui-for-asp-net-ajax). Vendors: [Progress](https://junglewise.ai/threats/vendors/progress).

## Quick answers

**Is CVE-2019-18935 exploited in the wild?** Yes. CVE-2019-18935 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.

**How severe is CVE-2019-18935?** Critical severity, with a CVSS score of 9.8, published 3 November 2021.

**Which products and versions are affected?** Telerik UI for ASP.NET AJAX through 2019.3.1023.

**Is there a fix for CVE-2019-18935?** A patch was published on 2020-01-14: Fixed in version 2020.1.114 where a default setting prevents the exploit Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2019-18935 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2019-18935?** Check whether you run Progress Telerik Ui For Asp.Net Ajax. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Telerik UI for ASP.NET AJAX through 2019.3.1023

## Timeline

- 2019-12-17: disclosed: Initial public disclosure via Packet Storm
- 2020-01-14: patched: Fixed in version 2020.1.114 where a default setting prevents the exploit
- 2021-11-03: kev added: Added to CISA Known Exploited Vulnerabilities Catalog

## Related threats

- [In Progress® Telerik® UI for AJAX versions 2024.4.1114 through 2026.1.421, the RadFilter control is vulnerable to…](https://junglewise.ai/threats/cve-2026-6023-in-progress-telerik-ui-for-ajax-versions-2024-4-1114-through-2026)
- [In Progress® Telerik® UI for AJAX prior to 2026.1.421, RadAsyncUpload contains an uncontrolled resource consumption…](https://junglewise.ai/threats/cve-2026-6022-in-progress-telerik-ui-for-ajax-prior-to-2026-1-421-radasyncupload)