CVE-2019-18935Known exploitationPublic exploitNetwork attack vector

Remote code execution via attacker-selected deserialization types

Published Dec 11, 2019 · Updated Oct 21, 2025

Deserialization in Telerik UI for ASP.NET AJAX 2019.3.1023 and earlier allows remote attackers to execute code via RadAsyncUpload requests. AsyncUploadHandler passes the attacker-selected type in rauPostData to JavaScriptSerializer.Deserialize, allowing object setters to load a malicious DLL. Exploitation requires a reachable upload handler, known or broken encryption keys, and disabled type whitelisting; code executes with the IIS worker process's permissions.

CVSS severity9.8
Critical
EPSS probability99.74%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in Telerik UI for ASP.NET AJAX 2019.3.1023 and earlier allows remote attackers to execute code via RadAsyncUpload requests. AsyncUploadHandler passes the attacker-selected type in rauPostData to JavaScriptSerializer.Deserialize, allowing object setters to load a malicious DLL. Exploitation requires a reachable upload handler, known or broken encryption keys, and disabled type whitelisting; code executes with the IIS worker process's permissions.

The record

CVE
CVE-2019-18935
Published
Dec 11, 2019
Updated
Oct 21, 2025
Vendor
Progress Software Corporation
Product
Telerik UI for ASP.NET AJAX
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 11, 2019CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Progress Software Corporation · Telerik UI for ASP.NET AJAXversion=n/a

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 2026Unavailable
Sep 23, 2026Unavailable
Sep 24, 2026Unavailable
Sep 25, 20261
Sep 26, 2026Unavailable
Sep 27, 20261
Sep 28, 20261
Latest reporting daySep 28, 2026
Latest daily unique IPs1
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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