CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. In version 1.9.0, CoreWCF SPNEGO SecurityContextToken negotiation can expose the proof key recovered from the RSTR when TransportWithMessageCredential with Windows client credentials and session establishment are used, allowing an observer to impersonate the authenticated Windows principal and decrypt or forge WS-SecureConversation traffic. This issue is fixed in version 1.9.1.
CVE-2026-54784
This high-severity CVE scores 7.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 93% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.4
- EG Score
- 7.4(medium)
- EG Risk
- 33(Track)EG Risk 33/100SSVC: Track
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 computedSeverity74% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 7.2%
- KEV
- Not listed
Published
June 19, 2026
Last Modified
July 10, 2026
Advisory Details (4)
Auto-updated Jul 8, 2026CoreWCF v1.9.1
Patch available: CoreWCF/CoreWCF v1.9.1
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1commit f216aa6929d4 (CoreWCF/CoreWCF)
Fix landed in CoreWCF/CoreWCF commit f216aa6929d4 — awaiting tagged release
https://github.com/CoreWCF/CoreWCF/commit/f216aa6929d41dc99cee098b1e69c260ec4c41c7commit 2afae08b2fa5 (CoreWCF/CoreWCF)
Patch available: CoreWCF/CoreWCF v1.9.1 (contains commit 2afae08b2fa5)
https://github.com/CoreWCF/CoreWCF/commit/2afae08b2fa5288428df89e8161116b816cf6b4bSPNEGO SecurityContextToken proof key wrapped without confidentiality · Advisory · CoreWCF/CoreWCF · GitHub
https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-2288-8h3r-cqggVendor Advisories for CVE-2026-54784(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
NuGet(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| CoreWCF.Primitives | 1.9.0 | 1.9.1 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 21× 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.
- 2026-07-23 03:19 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:25 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-13 22:31 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-06-19 21:25 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-54784?
When was CVE-2026-54784 disclosed?
Is CVE-2026-54784 actively exploited?
What is the CVSS score of CVE-2026-54784?
How do I remediate CVE-2026-54784?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54784
Is Your Infrastructure Affected by CVE-2026-54784?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.