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HIGH

CVE-2026-86158

CVSS v3

7.7

HIGH

EPSS Score

0.1 %

exploit probability, as of 2026-09-29

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
2026-09-29
Last Modified
2026-09-29

Frequently asked questions

What is CVE-2026-86158?

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.

Is CVE-2026-86158 actively exploited?

Active exploitation of CVE-2026-86158 has not been confirmed. Its EPSS score was 0.1% on 2026-09-29, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-86158?

CVE-2026-86158 has a CVSS v3 base score of 7.7 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

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