Skip to content
Fencer Vulns
high 7.4

CVE-2026-54784 json

CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality

published 2026-06-19 4 mo ago modified 2026-07-10 4 mo ago also EUVD-2026-42471 , GHSA-2288-8h3r-cqgg

cvss
7.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

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.

Patch / fix

  • nuget CoreWCF.Primitives 1.9.1
  • corewcf corewcf 1.9.1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
nuget CoreWCF.Primitives
>=1.9.0, <1.9.1
1.9.1

Affected products

  • CoreWCF CoreWCF

Classification

Weakness
  • CWE-311 Missing Encryption of Sensitive Data
  • CWE-523 Unprotected Transport of Credentials

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.