What’s Vulnerable › Vulnerabilities

CVE-2026-2878: Insufficient Entropy Vulnerability in Telerik UI for ASP.NET AJAX

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-25 · updated 2026-06-17
• Weakness: CWE-331

Description

In Progress® Telerik® UI for AJAX, versions prior to 2026.1.225, an insufficient entropy vulnerability exists in RadAsyncUpload, where a predictable temporary identifier, based on timestamp and filename, can enable collisions and file content tampering.

Affected products

• Progress Software Telerik UI for ASP.NET AJAX: before 2026.1.225 — fixed in 2026.1.225

How to fix

Upgrade to a fixed version: Progress Software Telerik UI for ASP.NET AJAX 2026.1.225. Check the vendor advisory for mitigations.

References

• https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/kb-security-insufficient-entropy-cve-2026-2878

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