Local authentication bypass via eager security initialization
Published Jul 8, 2026 · Updated Jul 8, 2026
Authentication bypass in CoreWCF before 1.8.1 and CoreWCF 1.9.0 allows local users to dispatch messages without PosixIdentity checks. UnixPosixIdentitySecurityUpgradeAcceptor eagerly creates an empty SecurityMessageProperty, so the framing pipeline's null sentinel falsely indicates that the application/unixposix upgrade negotiated remote security. A local user must reach a Unix domain socket configured for TransportCredentialOnly with PosixIdentity; the bypass exposes operations or data authorized through the asserted identity.
Summary
What happened
Authentication bypass in CoreWCF before 1.8.1 and CoreWCF 1.9.0 allows local users to dispatch messages without PosixIdentity checks. UnixPosixIdentitySecurityUpgradeAcceptor eagerly creates an empty SecurityMessageProperty, so the framing pipeline's null sentinel falsely indicates that the application/unixposix upgrade negotiated remote security. A local user must reach a Unix domain socket configured for TransportCredentialOnly with PosixIdentity; the bypass exposes operations or data authorized through the asserted identity.
The record
- CVE
- CVE-2026-54776
- Published
- Jul 8, 2026
- Updated
- Jul 8, 2026
- Vendor
- CoreWCF
- Product
- CoreWCF
- Classifications
- CWE-306
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 8, 2026CVE publishedPublication date reported by the CVE source.
- 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?
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- Affected versionversion=< 1.8.1
- Affected versionversion=>= 1.9.0, < 1.9.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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