CVE-2026-54784Network attack vector

Principal impersonation via unencrypted SCT proof key

Published Jul 8, 2026 · Updated Jul 8, 2026

Information disclosure in CoreWCF 1.9.0 allows remote attackers to recover an SCT proof key from a non-TLS SPNEGO negotiation. NTAuthenticationNet8.Encrypt calls NegotiateAuthentication.Wrap with requestEncryption set to false and ignores whether the result is encrypted, leaving the key cleartext inside the base64-encoded RSTR. TransportWithMessageCredential, Windows client credentials, session establishment, and a non-TLS network leg are required; the key permits principal impersonation and decryption or forgery of WS-SecureConversation traffic for the SCT lifetime.

CVSS severity7.4
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in CoreWCF 1.9.0 allows remote attackers to recover an SCT proof key from a non-TLS SPNEGO negotiation. NTAuthenticationNet8.Encrypt calls NegotiateAuthentication.Wrap with requestEncryption set to false and ignores whether the result is encrypted, leaving the key cleartext inside the base64-encoded RSTR. TransportWithMessageCredential, Windows client credentials, session establishment, and a non-TLS network leg are required; the key permits principal impersonation and decryption or forgery of WS-SecureConversation traffic for the SCT lifetime.

The record

CVE
CVE-2026-54784
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
CoreWCF
Product
CoreWCF
Classifications
CWE-523, CWE-311, T1040
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.9.0, < 1.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CoreWCF · CoreWCFversion=>= 1.9.0, < 1.9.1

Published CVSS scores

7.4GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-523Unprotected Transport of Credentials
CWE-311Missing Encryption of Sensitive Data
T1040Network Sniffing

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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