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

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

01What is this vulnerability?

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…

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2021-11-03. Ransomware use: Known.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

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07Related CVEs

08Timeline

• Published: 2019-12-11T00:00:00.000Z
• Last modified: 2025-10-21T23:35:56.289Z
• Added to CISA KEV: 2021-11-03
• BOD 22-01 due: 2022-05-03

09References

• www.telerik.com — https://www.telerik.com/support/whats-new/release-history
• codewhitesec.blogspot.com — https://codewhitesec.blogspot.com/2019/02/telerik-revisited.html
• www.telerik.com — https://www.telerik.com/support/kb/aspnet-ajax/details/allows-javascriptserializ…
• github.com — https://github.com/bao7uo/RAU_crypto
• know.bishopfox.com — https://know.bishopfox.com/research/cve-2019-18935-remote-code-execution-in-tele…
• github.com — https://github.com/noperator/CVE-2019-18935
• packetstormsecurity.com — http://packetstormsecurity.com/files/155720/Telerik-UI-Remote-Code-Execution.htm…
• www.telerik.com — https://www.telerik.com/support/whats-new/aspnet-ajax/release-history/ui-for-asp…
• packetstormsecurity.com — http://packetstormsecurity.com/files/159653/Telerik-UI-ASP.NET-AJAX-RadAsyncUplo…
• www.bleepingcomputer.com — https://www.bleepingcomputer.com/news/security/us-federal-agency-hacked-using-ol…