# CVE-2026-13181 — Progress Software Telerik UI for ASP.NET AJAX

> As of 2026-07-24, CVE-2026-13181 is a HIGH-severity vulnerability in Progress Software Telerik UI for ASP.NET AJAX, CVSS v3.1 8.1, EPSS 0.5% (41.1th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-13181, most recently “Telerik UI for ASP.NET AJAX — Padding Oracle Chained to Unauthenticated Deserialization RCE (CVE-2026-13181–13184)”.

**Last updated:** 2026-07-24

## What is CVE-2026-13181?

In Progress® Telerik® UI for AJAX prior to v2026.2.708, forged upload metadata can influence AsyncUploadTypeName processing and trigger unsafe attacker-controlled type resolution, enabling remote code execution in affected deployments.

The record classifies CVE-2026-13181 under weakness class [CWE-470](https://cwe.mitre.org/data/definitions/470.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 75 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 8.1 — HIGH (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **EPSS (FIRST):** 0.5% probability of exploitation in the next 30 days, higher than 41.1% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 7.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-22, last modified 2026-07-24

## Is CVE-2026-13181 being exploited?

Weaponised exploit code for CVE-2026-13181 is publicly available. 1 public proof-of-concept repository is tracked for this identifier.

- [HORKimhab/CVE-2026-13181-CVE-2026-13182-CVE-2026-13183-CVE-2026-13184](https://github.com/HORKimhab/CVE-2026-13181-CVE-2026-13182-CVE-2026-13183-CVE-2026-13184) (github)

## Affected products and versions

- **Progress Software**: Telerik UI for ASP.NET AJAX

## How to fix CVE-2026-13181

Vendor advisory: [https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/kb-security-rau-asyncuploadtypename-deserialization-CVE-2026-13181](https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/kb-security-rau-asyncuploadtypename-deserialization-CVE-2026-13181). Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

## Threat activity tracking CVE-2026-13181

1 tracked threat in the Threadlinqs corpus references CVE-2026-13181, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Telerik UI for ASP.NET AJAX — Padding Oracle Chained to Unauthenticated Deserialization RCE (CVE-2026-13181–13184)](https://intel.threadlinqs.com/threat/TL-2026-2369) — HIGH · 2026-09-07

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-09-08. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [telerik.com — vendor advisory](https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/kb-security-rau-asyncuploadtypename-deserialization-CVE-2026-13181)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-13181
Full detection coverage and IOCs for threats exploiting CVE-2026-13181 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp