High severity7.7NVD Advisory· Published Sep 29, 2026

CVE-2026-86158

Description

Missing authentication in the local .NET backend (Fiddler.WebUi) of Progress Software Fiddler Everywhere 8.0.2 allows a local unauthenticated attacker to mint OAuth tokens and read the machine-in-the-middle root certificate through an unauthenticated localhost HTTP and SignalR RPC channel.

Affected products

Process Software/Fiddler Everywherellm-create
Range: <8.0.2
Telerik/Fiddler Everywherellm-create
Range: <8.0.2

Patches

Vulnerability mechanics

References

www.telerik.com/fiddler/fiddler-everywhere/documentation/knowledge-base/kb-security-exposed-dangerous-method-or-function-cve-2026-aaaaanvd

News mentions

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ransomware	0.000