CVE-2026-86158CWE-306

CVE-2026-86158

High · published September 29, 2026

CVSS v3.1
7.7
EPSS
0%
Percentile
0.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.7 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00087 · 0.3th percentile
Weakness
CWE-306 · Missing Authentication for Critical Function
Published
2026-09-29T11:16Z
References (1)
https://www.telerik.com/fiddler/fiddler-everywhere/documentation/knowledge-base/kb-security-missing-authentication-for-critical-function-cve-2026-86158 · [email protected]
EPSS history
Timeline
  • 30 SEP 03:29Z
    EPSS moved — → 0%
    epss
  • 29 SEP 06:34Z
    Missing Authentication in the local .NET backend of Progress Telerik Fiddler Everywhere
    cvelistv5