VYPR
High severity7.4GHSA Advisory· Published Jun 19, 2026· Updated Jun 19, 2026

CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality

CVE-2026-54784

Description

Impact

When the proof key recovered from the RSTR can be observed by a party that is not the legitimate client, that party can impersonate the authenticated Windows principal for the lifetime of the SCT (default ~10 hours) and decrypt or forge any subsequent WS‑SecureConversation traffic that uses keys derived from the SCT.

Preconditions

Using security mode TransportWithMessageCredential with client credential type Windows, along with session establishment (which triggers use of WS-SecureConversation).

Patches

Fixed in CoreWCF v1.9.1

Workarounds

Ensure communication is protected by SSL/TLS to prevent capturing of SCT negotiation handshake.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

1

Patches

Vulnerability mechanics

No source-code context for this CVE — mechanics is only generated when we can read the actual fix diff. Without that, the four sections (root cause, attack vector, affected code, fix) would be speculation rather than analysis.

References

2

News mentions

0

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