# CVE-2026-6023: Deserialization of Untrusted Data Vulnerability in Telerik UI for ASP.NET AJAX

> Attackers can achieve remote code execution by tampering with client-exposed filter state in the RadFilter control.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Apr 2026
- **Updated:** 23 Apr 2026
- **Also known as:** GHSA-mcrv-gh25-252c

## What is CVE-2026-6023?

CVE-2026-6023 is a high-severity unsafe deserialization vulnerability in Progress Software Telerik UI for ASP.NET AJAX, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-6023?

It affects 1 product.


Products: Progress Telerik Ui for Asp.net Ajax.

## How do I fix CVE-2026-6023?

No fix has been published for CVE-2026-6023 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6023 being exploited?

There is no known exploitation of CVE-2026-6023 in the wild and no public exploit code.

## Other vulnerabilities in Progress Software Telerik UI for ASP.NET AJAX

- [CVE-2017-11357](https://insights.sbomify.com/CVE-2017-11357/): Telerik UI for ASP.NET AJAX Insecure Direct Object Reference (critical 9.8, exploited in the wild)
- [CVE-2021-28141](https://insights.sbomify.com/CVE-2021-28141/): Missing authorization in n/a (critical 9.8)
- [CVE-2019-19790](https://insights.sbomify.com/CVE-2019-19790/): Path traversal in n/a (critical 9.8)
- [CVE-2026-13181](https://insights.sbomify.com/CVE-2026-13181/): RadAsyncUpload AsyncUploadTypeName Type Resolution Vulnerability in Telerik UI for ASP.NET AJAX (high 8.1)
- [CVE-2026-13185](https://insights.sbomify.com/CVE-2026-13185/): PersistenceFramework Cookie Deserialization Vulnerability in Telerik UI for ASP.NET AJAX (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6023 and fix it if it is affected.

What it is: CVE-2026-6023 is a high-severity unsafe deserialization vulnerability in Progress Software Telerik UI for ASP.NET AJAX, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-6023 in the wild and no public exploit code.

Affected product: Progress Software Telerik UI for ASP.NET AJAX. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-6023/ (Markdown: https://insights.sbomify.com/CVE-2026-6023/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6023
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6023
- OSV: https://osv.dev/vulnerability/CVE-2026-6023

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-6023/
Summaries are generated and may contain mistakes; the official description above is the record.