EUVD-2026-92426

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, front-end request desynchronization is possible in the proxy request forwarding component. A request that contains both a Content-Length and a Transfer-Encoding header is forwarded with both headers present,...

CVE-2026-77803

Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021 , contains a front-end request desynchronization vulnerability in the proxy request forwarding component. The root cause is that the software forwards requests containing both Content-Length and Transfer-Encoding ...

CVE-2026-77803: Inconsistent Interpretation of HTTP Requests

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, front-end request desynchronization is possible in the proxy request forwarding component. A request that contains both a Content-Length and a Transfer-Encoding header is forwarded with both headers present,...

PT-2026-105988

Name of the Vulnerable Software and Affected Versions Progress Telerik Fiddler Classic for Windows versions prior to 6.0.20262.10021 Description Front-end request desynchronization is possible in the proxy request forwarding component. When a request contains both Content-Length and...