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Weekly Signal
Live intelligence Updated 19 Aug 2026 · 20:27 UTC

Progress, Telerik · Telerik Ui For Asp.net Ajax, Ui For Asp.net Ajax

CVE-2019-18935

Progress Telerik UI for ASP.NET AJAX Deserialization of Untrusted Data Vulnerability

Recommended action

Treat this as an immediate remediation priority. Apply updates per vendor instructions.

View response plan
CVSS9.8
EPSS99.7%
KEVYes
ExploitationConfirmed exploitation
PatchPatch or guidance available ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 99.7%; technical severity is CVSS 9.8.

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.)

Who should care

  • Teams operating Telerik Ui For Asp.net Ajax, Ui For Asp.net Ajax
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether Telerik Ui For Asp.net Ajax, Ui For Asp.net Ajax is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Apply updates per vendor instructions.
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Vendor remediation

Patch and remediation links

Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-502
Affected versions
Progress Telerik Ui For Asp.net Ajax; Telerik Ui For Asp.net Ajax (Start Including: 2011.1.315, End Including: 2020.1.114)
Published
11 December 2019
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 99.7%
  4. Signal calculated at 88

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.