CVE-2026-6023: Progress Software Telerik UI for ASP.NET AJAX · Deserialization of Untrusted Data
Affects Progress Software Telerik UI for ASP.NET AJAXSource CVE Database V5
Not known to be exploited · CVSS 8.1 High : upgrade to 2026.1.421 soon.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2026.1.421
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade Progress Software Telerik UI for ASP.NET AJAX to 2026.1.421.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Progress SoftwareTelerik UI for ASP.NET AJAX | Affected
| Fixed in
|
NuGettelerik.ui.for.aspnet.ajaxpkg:nuget/telerik.ui.for.aspnet.ajaxOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, avoid exposing the RadFilter control's serialized filter state to clients or implement strict validation and integrity checks on any deserialized data.
Description
In Progress® Telerik® UI for AJAX versions 2024.4.1114 through 2026.1.421, the RadFilter control is vulnerable to insecure deserialization when restoring filter state if the state is exposed to the client. If an attacker tampers with this state, a server-side remote code execution is possible.