Progress Telerik Fiddler Classic < 6.0.20262.10021 Multiple Vulnerabilities

The version of Progress Telerik Fiddler Classic installed on the remote Windows host is prior to 6.0.20262.10021. It is, therefore, affected by multiple vulnerabilities: - An insufficient integrity check on external helper tools allows a local low-privileged attacker to replace a helper executabl...

CVE-2026-77805 Weak Executable Signature Verification Vulnerability in Progress® Telerik® Fiddler® Classic

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, the integrity check applied to the external helper tools launched by the application is insufficient. Before executing a helper tool, the application only verifies that the file carries a valid Authenticode...

EUVD-2026-92428

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, the integrity check applied to the external helper tools launched by the application is insufficient. Before executing a helper tool, the application only verifies that the file carries a valid Authenticode...

EUVD-2026-92427

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, a time-of-check time-of-use TOCTOU race condition exists in the installation of the HTTPS interception root certificate into the Local Computer certificate store. Fiddler writes the certificate to a temporary...

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-2026-77802

Progress Telerik Fiddler Classic for Windows versions prior to v6.0.20262.10021 are vulnerable to HTTP request smuggling in the proxy request forwarding component. The issue arises because the software forwards requests with multiple conflicting Content-Length headers verbatim, while only using t...

CVE-2026-77802 HTTP Request Smuggling Vulnerability in Progress® Telerik® Fiddler® Classic

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, HTTP request smuggling is possible in the proxy request forwarding component. Requests containing multiple Content-Length headers with conflicting values are forwarded verbatim to the origin server, while...

PT-2026-105990

In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, the integrity check applied to the external helper tools launched by the application is insufficient. Before executing a helper tool, the application only verifies that the file carries a valid Authenticode...

PT-2026-105987

Name of the Vulnerable Software and Affected Versions Progress Telerik Fiddler Classic for Windows versions prior to 6.0.20262.10021 Description HTTP request smuggling is possible in the proxy request forwarding component. This occurs when requests containing multiple Content-Length headers with...