Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2019-18935

Telerik UI for ASP.NET AJAX Deserialization

Progress Software / Telerik UI for ASP.NET AJAX

Watch CVE-2019-18935 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
99.7%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2019-18935 is an unauthenticated vulnerability affecting Progress Software Telerik UI for ASP.NET AJAX. Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Progress Software / Telerik UI for ASP.NET AJAX.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Telerik UI for ASP.NET AJAX Deserialization

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.)

Published
11 Dec 2019
Exploitation Reported
03 Nov 2021
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

dotnet metasploit ransomware cisa malware

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 03 Nov 2021

A trusted third party reported exploitation.

Used in malware

CISA

Recorded 03 Nov 2021

Malware families have been linked to exploitation of this CVE.

Proof of concept available

GitHub

Recorded 12 Dec 2019

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2021-11-03 00:00 UTC
The Shadowserver 2026-07-12 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/http/telerik_rau_deserialization.rb 28 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

99.7%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Deserialization of Untrusted Data CWE-502

Recent mention · RecordedFuture

August 2026 CVE Landscape

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Read full advisory

All CVSS Scores

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 7.5 High

AV:N/AC:L/Au:N/C:P/I:P/A:P

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

telerik_rau_deserialization

metasploit · Created Unknown

Metasploit module for CVE-2019-18935

Timeline

From disclosure to observed exploitation

  1. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attested by an external source

  2. 15:02 UTC

    Metasploit module available

    Exploit module available

  3. 15:02 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  5. 00:00 UTC

    First public exploitation report

    Exploit observed in malware

  6. 00:00 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2019-18935

Sample API response 
{
  "cve_id": "CVE-2019-18935",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.99737,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}