Vulnerability in Corewcf

CVE-2026-54784

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (18.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-54784: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

  • Corewcf — versions >= 1.9.0, < 1.9.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-54784?
CVE-2026-54784 is a high-severity vulnerability in Corewcf, classified under Missing Encryption of Sensitive Data. CVSS score: 7.4/10. Published 2026-07-08.
How severe is CVE-2026-54784?
High severity. CVSS v3 base score is 7.4 out of 10.