CVE-2026-54776— CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade
Possible ATT&CK Techniques 1AI
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I. Basic Information for CVE-2026-54776
Vulnerability Information
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Vulnerability Title
CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
关键功能的认证机制缺失
Source: CVE Program / CVE List V5
Vulnerability Title
CoreWCF 授权问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
CoreWCF是CoreWCF团队开源的一个开源项目,旨在为 .NET Core 和 .NET 5+ 提供 WCF(Windows Communication Foundation)的替代实现。 CoreWCF 1.8.1之前版本和1.9.1之前版本存在授权问题漏洞，该漏洞源于在Unix Domain Sockets上托管时，PosixIdentity客户端凭据可跳过身份验证升级，绕过UnixPosixIdentitySecurityUpgradeProvider中的框架层身份检查，导致授权问题。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-54776
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Patches & Fixes for CVE-2026-54776 (3)
Vendor Advisories for CVE-2026-54776 (1)
Vendor Pages for CVE-2026-54776 (1)
Other References for CVE-2026-54776 (1)
Same Patch Batch · CoreWCF · 2026-07-08 · 13 CVEs total
| CVE-2026-54782 | 10.0 CRITICAL | CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation |
| CVE-2026-54772 | 7.5 HIGH | CoreWCF: Pre-authentication infinite-loop CPU exhaustion in CoreWCF net.tcp / net.pipe / n |
| CVE-2026-54783 | 7.4 HIGH | CoreWCF: XML Signature Wrapping in WS-Security endorsing/supporting signature verification |
| CVE-2026-54774 | 7.4 HIGH | CoreWCF: SamlSerializer skips SignatureValue verification when SAML signing token is not a |
| CVE-2026-54781 | 7.4 HIGH | CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced |
| CVE-2026-54784 | 7.4 HIGH | CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality |
| CVE-2026-54775 | 6.5 MEDIUM | CoreWCF: Kafka consume pump halts permanently on a Kafka tombstone (null-value record), ca |
| CVE-2026-54777 | 6.5 MEDIUM | CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance |
| CVE-2026-54778 | 6.2 MEDIUM | CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution |
| CVE-2026-54779 | 5.9 MEDIUM | CoreWCF: SAML token replay protection is inoperative |
| CVE-2026-54773 | 5.9 MEDIUM | CoreWCF: WS-Security signature substitution via document-wide Signature lookup |
| CVE-2026-54780 | 3.7 LOW | CoreWCF: WS-Security Reference DigestMethod Algorithm-Suite Bypass |
IV. Related Vulnerabilities
Same product: CoreWCF
- CVE-2026-54782
CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 tok - CVE-2026-54781
CoreWCF: SAML SubjectConfirmation methods and holder-of-key - CVE-2026-54784
CoreWCF: SPNEGO SecurityContextToken proof key wrapped witho - CVE-2026-54774
CoreWCF: SamlSerializer skips SignatureValue verification wh - CVE-2026-54783
CoreWCF: XML Signature Wrapping in WS-Security endorsing/sup
Same vendor: CoreWCF
- CVE-2026-54782
CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 tok - CVE-2026-54781
CoreWCF: SAML SubjectConfirmation methods and holder-of-key - CVE-2026-54784
CoreWCF: SPNEGO SecurityContextToken proof key wrapped witho - CVE-2026-54774
CoreWCF: SamlSerializer skips SignatureValue verification wh - CVE-2026-54783
CoreWCF: XML Signature Wrapping in WS-Security endorsing/sup
Same weakness: CWE-306
- CVE-2026-19971
LB-Link WR1210M Backup Endpoint backup.cgi main missing auth - CVE-2026-74245
Quay: unauthenticated exported logs download in quay - CVE-2026-74243
Quay: unauthenticated secscan notification endpoint in quay - CVE-2026-19908
PAX Technology Q80 XCB Daemon Missing Authentication Vulnera - CVE-2026-50027
mcp-memory-service: Missing Authentication on Document API E
V. Comments for CVE-2026-54776
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