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

Medium 5.3 Published 25 Feb 2026 Updated 27 Feb 2026

Attackers can tamper with file content in RadAsyncUpload due to predictable temporary identifiers caused by insufficient entropy.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-2878?

CVE-2026-2878 is a medium-severity vulnerability in Progress Software Telerik UI for ASP.NET AJAX, published on 25 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official 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.

Weakness: CWE-331

Which versions are affected by CVE-2026-2878?

It affects 1 product.

Products include Progress Telerik Ui for Asp.net Ajax.

How do I fix CVE-2026-2878?

No fix has been published for CVE-2026-2878 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-2878 being exploited?

There is no known exploitation of CVE-2026-2878 in the wild and no public exploit code.

Sources

Also known as GHSA-wqx8-r5jg-36w6.