# CVE-2026-13188: DialogHandler Parameters Tampering Vulnerability in Telerik UI for ASP.NET AJAX

> Attackers can tamper with DialogHandler parameters to alter server-side behavior, potentially enabling chained exploitation in Telerik UI for ASP.NET AJAX.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Jul 2026
- **Updated:** 22 Jul 2026
- **Also known as:** GHSA-gggw-r635-4jx6

## What is CVE-2026-13188?

CVE-2026-13188 is a medium-severity vulnerability in Progress Software Telerik UI for ASP.NET AJAX, published on 22 Jul 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 prior to v2026.2.708, DialogHandler request parameters may be tampered with, potentially altering dialog server-side behavior and enabling chained exploitation.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-13188?

It affects 1 product.


Products: Progress Telerik Ui for Asp.net Ajax.

## How do I fix CVE-2026-13188?

No fix has been published for CVE-2026-13188 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-13188 being exploited?

There is no known exploitation of CVE-2026-13188 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-2026-13188 and fix it if it is affected.

What it is: CVE-2026-13188 is a medium-severity vulnerability in Progress Software Telerik UI for ASP.NET AJAX, published on 22 Jul 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-2026-13188 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-2026-13188/ (Markdown: https://insights.sbomify.com/CVE-2026-13188/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-13188
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13188
- OSV: https://osv.dev/vulnerability/CVE-2026-13188

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-13188/
Summaries are generated and may contain mistakes; the official description above is the record.