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CVE-2026-54784

31
FAUCET Score

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.

First published: Jul 8, 2026Last modified: Jul 8, 2026

Impacted Technologies

VendorProductVersion(s)CPE
CoreWCFCoreWCF
>= 1.9.0, < 1.9.1CNA affected

CVSS Data

CVSS version used by this source: 3.1

7.4HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.18%
Probability of exploitation in next 30 days
EPSS Percentile
7.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0018 is in the 0th percentile among its peer group of 8,920 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

nugetpatch availablevia ghsa
Product: CoreWCF.PrimitivesFixed in: 1.9.1

Vendor Advisories (1)

nugetGHSA-2288-8h3r-cqgghigh

CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality

Jun 19, 2026

References

github.com / CoreWCF/CoreWCF/commit/2afae08b2fa5288428df89e8161116b816cf6b4b
github.com / CoreWCF/CoreWCF/commit/f216aa6929d41dc99cee098b1e69c260ec4c41c7
github.com / CoreWCF/CoreWCF/releases/tag/v1.9.1
github.com / CoreWCF/CoreWCF/security/advisories/GHSA-2288-8h3r-cqgg