CVE-2019-18935 — Telerik Ui For Asp.net Ajax

What is CVE-2019-18935?

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.)

The record classifies CVE-2019-18935 under weakness class CWE-502. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 2499 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST): 99.7% probability of exploitation in the next 30 days, higher than 99.9% of all scored CVEs
CISA KEV: Listed since 2021-11-03, federal remediation deadline 2022-05-03 — used in known ransomware campaigns
Threadlinqs priority: 10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
Published: 2019-12-11, last modified 2025-10-21

Is CVE-2019-18935 being exploited?

CISA added CVE-2019-18935 to the Known Exploited Vulnerabilities catalog on 2021-11-03, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2022-05-03 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. Weaponised exploit code for CVE-2019-18935 is publicly available. 11 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 48 in the Threadlinqs vulnerability feed.

noperator/CVE-2019-18935 (github)
bao7uo/RAU_crypto (github)
murataydemir/CVE-2019-18935 (github)
ThanHuuTuan/Telerik_CVE-2019-18935 (github)
dust-life/CVE-2019-18935-memShell (github)
ekkoo-z/CVE-2019-18935-bypasswaf (github)
random-robbie/CVE-2019-18935 (github)
ThanHuuTuan/CVE_2019_18935 (github)

Affected products and versions

Telerik: Ui For Asp.net Ajax

How to fix CVE-2019-18935

The record marks a vendor fix as available for CVE-2019-18935. Patch reference: https://docs.telerik.com/devtools/aspnet-ajax/knowledge-base/common-allows-javascriptserializer-deserialization. Vendor advisory: https://www.telerik.com/support/kb/aspnet-ajax/details/allows-javascriptserializer-deserialization. Because CVE-2019-18935 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2022-05-03. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2019-18935

4 tracked threats in the Threadlinqs corpus reference CVE-2019-18935, either in the campaign’s CVE list or as an indicator on the campaign record.

CVE-2019-18935 Telerik UI Deserialization Exploited to Deploy Web Shells and a WordPress Scanner on IIS Servers — CRITICAL · 2026-09-28
Telerik UI for ASP.NET AJAX — Padding Oracle Chained to Unauthenticated Deserialization RCE (CVE-2026-13181–13184) — HIGH · 2026-09-07
Chinese-speaking threat group UAT-10147 uses agentic AI to automate exploitation of internet-facing web servers — HIGH · 2026-08-21
APT35 (Charming Kitten) GCC Pre-Positioning Cyber Reconnaissance Campaign Enabling Kinetic Targeting — CRITICAL · 2026-04-09

Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10. This product uses the NVD API but is not endorsed or certified by the NVD.

Other references

Showing 5 of 10 recorded references.