CVE-2026-54773

CoreWCF: WS-Security signature substitution via document-wide Signature lookup

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF WS-Security signature verification performs a document-wide ds:Signature lookup, allowing an unauthenticated remote attacker to place a SOAP header before wsse:Security and cause WSSecurityOneDotZeroReceiveSecurityHeader to verify an attacker-supplied signature instead of the security header signature. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54777

CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF NetNamedPipe transport accepts attachment to a pre-existing named pipe instance, allowing local interception of NetNamedPipe traffic when an attacker races NamedPipeListener startup between shared memory GUID publication and service named pipe creation. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54780

CoreWCF: WS-Security Reference DigestMethod Algorithm-Suite Bypass

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, the CoreWCF WS-Security 1.0 receive pipeline validates ds:SignedInfo SignatureMethod against the configured SecurityAlgorithmSuite but does not validate each ds:Reference DigestMethod, allowing a sender to use a rejected digest algorithm such as SHA-1 while the message is still accepted. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 3.7 Low EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54774

CoreWCF: SamlSerializer skips SignatureValue verification when SAML signing token is not an X.509 certificate

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, SamlSerializer skips final SignatureValue verification when a CoreWCF service validates SAML tokens using a non-X.509 signing token, allowing an attacker to reference a non-X.509 SecurityToken key identifier and bypass assertion signature verification. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54781

CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF SAML token validation does not enforce SubjectConfirmation method URIs or holder-of-key proof keys in SamlSecurityTokenHandler, allowing holder-of-key downgrade or custom confirmation method assertions to authenticate a subject without proving authority over the assertion. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54782

CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF SAML 1.1 and SAML 2.0 token validation does not correctly resolve the issuer signing key or require signed tokens when IdentityConfiguration is used with federated bindings, allowing an unauthenticated remote attacker to impersonate any principal the trusted STS could issue. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 10 Critical EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54775

CoreWCF: Kafka consume pump halts permanently on a Kafka tombstone (null-value record), causing persistent endpoint denial of service.

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, a CoreWCF service listening on a Kafka topic stops processing new records from that topic when KafkaTransportPump receives a null-value tombstone record, causing a persistent endpoint denial of service for attackers with produce permission. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54772

CoreWCF: Pre-authentication infinite-loop CPU exhaustion in CoreWCF net.tcp / net.pipe / net.uds framing handshake

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, an unauthenticated remote attacker that can reach a NetTcpBinding, NetNamedPipeBinding, or UnixDomainSocketBinding endpoint can trigger premature EOF handling in the CoreWCF net.tcp, net.pipe, or net.uds framing handshake and pin one server thread-pool worker at full CPU per connection. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54779

CoreWCF: SAML token replay protection is inoperative

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF SAML token replay protection is inoperative because DefaultTokenReplayCache.TryAdd does not reject duplicate tokens when DetectReplayedTokens is enabled, allowing a captured token to be reused. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54778

CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF UnixDomainSocket POSIX peer identity resolution uses non-reentrant getpwuid and getgrgid calls, allowing concurrent connections to attribute one connection's identity to another or crash the host process under contention. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 6.2 Medium EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54784

CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality

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.

CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54776

CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, a CoreWCF service hosted on Unix Domain Sockets with PosixIdentity client credentials can accept connections that skip the application/unixposix stream upgrade before dispatching messages, bypassing framing-layer identity checks in UnixPosixIdentitySecurityUpgradeProvider. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 4.4 Medium EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2026-54783

CoreWCF: XML Signature Wrapping in WS-Security endorsing/supporting signature verification allows replay of captured signed messages

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF WS-Security endorsing and supporting signature verification does not ensure the selected ds:Signature covers the expected Security header target, allowing an attacker with one captured signed SOAP envelope to replay arbitrary service operations as the victim principal. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf

CVE-2024-28252

CoreWCF NetFraming based services can leave connections open when they should be closed

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. If you have a NetFraming based CoreWCF service, extra system resources could be consumed by connections being left established instead of closing or aborting them. There are two scenarios when this can happen. When a client established a connection to the service and sends no data, the service will wait indefinitely for the client to initiate the NetFraming session handshake. Additionally, once a client has established a session, if the client doesn't send any requests for the period of time configured in the binding ReceiveTimeout, the connection is not properly closed as part of the session being aborted. The bindings affected by this behavior are NetTcpBinding, NetNamedPipeBinding, and UnixDomainSocketBinding. Only NetTcpBinding has the ability to accept non local connections. The currently supported versions of CoreWCF are v1.4.x and v1.5.x. The fix can be found in v1.4.2 and v1.5.2 of the CoreWCF packages. Users are advised to upgrade. There are no workarounds for this issue.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Corewcf

Products

Corewcf