CVE-2026-86158

HIGHPre-NVD 7.77.7—
EchelonGraph scoreHIGH confidence

Score 7.7 from GitHub Security Advisory (severity: HIGH) published 2026-09-29. A secondary CVSS source baseline 7.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.7EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: <0.1%CVSS: 7.7Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

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 v3
7.7
EG Score
7.7HIGHhigh confidence
EG Risk
35
EG Risk 35/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity77% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
<0.1%
EPSS %ILE
below the 1st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 29, 2026

Last Modified

September 30, 2026

References (1)

Vendor Advisories for CVE-2026-86158(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 28× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 10:17 UTCEG score recompute
  2. 2026-10-05 10:17 UTCGHSA enrichment
  3. 2026-10-04 23:22 UTCEPSS rescore
  4. 2026-10-04 21:38 UTCGHSA enrichment
  5. 2026-10-04 09:00 UTCGHSA enrichment
  6. 2026-10-03 20:21 UTCEG score recompute
  7. 2026-10-03 20:21 UTCGHSA enrichment
  8. 2026-10-03 07:41 UTCGHSA enrichment
  9. 2026-10-02 19:00 UTCEG score recompute
  10. 2026-10-02 19:00 UTCGHSA enrichment
  11. 2026-10-02 17:57 UTCEPSS rescore
  12. 2026-10-02 06:21 UTCGHSA enrichment
  13. 2026-10-01 17:43 UTCGHSA enrichment
  14. 2026-10-01 05:04 UTCGHSA enrichment
  15. 2026-09-30 16:26 UTCEG score recompute
  16. 2026-09-30 16:26 UTCGHSA enrichment
  17. 2026-09-30 15:39 UTCEG score recompute
  18. 2026-09-30 15:39 UTCGHSA enrichment
  19. 2026-09-30 15:04 UTCEPSS rescore
  20. 2026-09-30 12:59 UTCEG score recompute
  21. 2026-09-30 12:59 UTCGHSA enrichment
  22. 2026-09-30 10:51 UTCGHSA enrichment
  23. 2026-09-29 22:10 UTCGHSA enrichment
  24. 2026-09-29 20:16 UTCEG score recompute
  25. 2026-09-29 20:16 UTCGHSA enrichment
Show 3 more
  1. 2026-09-29 07:35 UTCEG score recompute
  2. 2026-09-29 06:41 UTCEG score recompute
  3. 2026-09-29 06:39 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-86158?
CVE-2026-86158 is a high vulnerability published on September 29, 2026. 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.
When was CVE-2026-86158 disclosed?
CVE-2026-86158 was first published on September 29, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-86158 actively exploited?
CVE-2026-86158 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a <0.1% probability of exploitation in the next 30 days (below the 1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-86158?
CVE-2026-86158 has a CVSS base score of 7.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-86158?
No fix for CVE-2026-86158 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-86158 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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