CVE-2019-18935
CriticalExploitedPublic exploitProgress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function.
Published Mar 19, 2021 · Updated Oct 21, 2025
Key Facts
Patch immediately- CVE-2019-18935 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Ui For Asp.net Ajax (Telerik).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since May 7, 2020 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 100% probability of exploitation in the next 30 days.
- Fixed versions are available, including Ui For Asp.net Ajax <=2020.1.114, Ui For Asp.net Ajax 2020.1.114.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
100%
Higher than 99.9% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings, used by ransomware
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2019-18935 brief as a PDF
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Description
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.)
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | May 3, 2022 | Known |
| Industry KEV feed | May 7, 2020 | May 3, 2022 | Known |
| CIRCL KEV | Nov 3, 2021 | May 3, 2022 | Known |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
1 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Ui For Asp.net AjaxTelerik | See advisory | 2020.1.114 |
Patched Releases
Ui For Asp.net Ajax
<=2020.1.114
Timeline
Added to Industry KEV feed
May 7, 2020
Publicly disclosed
Mar 19, 2021
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Oct 21, 2025
Weakness Type
- CWE-502 Deserialization of Untrusted Data
References
- advisoryhttp://packetstormsecurity.com/files/155720/Telerik-UI-Remote-Code-Execution.html
- advisoryhttps://us-cert.cisa.gov/ics
- advisoryhttps://us-cert.cisa.gov/ics/advisories/icsa-21-077-02
- advisoryhttps://us-cert.cisa.gov/report
- advisoryhttps://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
FAQ
Common Questions.
Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function.
Affected: Ui For Asp.net Ajax (Telerik). The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since May 7, 2020 and is known to be used in ransomware campaigns.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of May 3, 2022.
Public exploit code is available.
Fixed versions are available, including Ui For Asp.net Ajax <=2020.1.114, Ui For Asp.net Ajax 2020.1.114.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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