Vulnerability details

CVE-2026-86158

Progress Software Progress® Telerik® Fiddler® Everywhere

Missing Authentication in the local .NET backend of Progress Telerik Fiddler Everywhere

CVSS 3.1

7.7High

Official 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.

CVSS scores

Score	Version	Source	Vector
7.7High	3.1	CVEProject cvelistV5 (CNA) (ProgressSoftware)	`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

Affected products

Vendor	Product	Versions	Source
Progress Software	Progress® Telerik® Fiddler® Everywhere	1.0.0 ≤ v < 8.2.0	CVEProject cvelistV5 (CNA)

References and advisories

https://www.telerik.com/fiddler/fiddler-everywhere/documentation/knowledge-base/kb-security-missing-authentication-for-critical-function-cve-2026-86158 vendor-advisory

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Details

Published: 2026-09-29
Last updated: 2026-09-30
State: Published
Assigner (CNA): ProgressSoftware

Exploit prediction (EPSS)

0.08%

Probability of exploitation in 30 days

0.3%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: No
Exploitation: None
Technical impact: Total

Weaknesses (CWE)

CWE-306
Missing Authentication for Critical Function