CyberSecBulletin
CVE-2026-13187NVD status: Analyzed

Telerik UI for ASP.NET AJAX: Use of Externally-Controlled Input to Select Classes or Code

Published Updated By the CyberSecBulletin desk

CVE-2026-13187 is a high-severity use of externally-controlled input to select classes or code vulnerability in Telerik UI for ASP.NET AJAX from Progress Software, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 2026.2.708 as the first without the flaw, so updating Telerik UI for ASP.NET AJAX to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.34% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Telerik UI for ASP.NET AJAX to 2026.2.708 or a later version.
  2. Read the advisory on telerik.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Progress SoftwareTelerik UI for ASP.NET AJAX2011.2.712 up to, but not including, 2026.2.7082026.2.708

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (progress.com).

Official description

In Progress® Telerik® UI for AJAX prior to v2026.2.708, DialogHandler provider type input may be tampered with, potentially altering dialog processing and enabling chained exploitation.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use of Externally-Controlled Input to Select Classes or Code

The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.

How developers prevent this class of flaw

  • Refactor your code to avoid using reflection.
  • Do not use user-controlled inputs to select and load classes or code.
  • Apply strict input validation by using allowlists or indirect selection to ensure that the user is only selecting allowable classes or code.

More Use of Externally-Controlled Input to Select Classes or Code vulnerabilities (CWE-470)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Telerik UI for ASP.NET AJAX

All Telerik UI for ASP.NET AJAX vulnerabilities

Recent Use of Externally-Controlled Input to Select Classes or Code vulnerabilities

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