RCE risk in widely-used Telerik UI for AJAX RadFilter; could impact many .NET apps
CVE-2026-6023
RCE via insecure deserialization in Telerik RadFilter when client state is tampered
Is CVE-2026-6023 being exploited?
Not confirmed. CVE-2026-6023 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.54% probability of exploitation in the next 30 days.
How severe is CVE-2026-6023?
CVE-2026-6023 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-6023?
Yes. A fix has been recorded for CVE-2026-6023. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-6023 affect?
CVE-2026-6023 affects Telerik UI for AJAX RadFilter (versions 2024.4.1114–2026.1.421). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-6023?
Patch/upgrade to fixed version asap
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Server-side remote code execution via tampered client-exposed filter state
Immediate action required
- affected>= 2024.4.1114 and < 2026.1.421
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.