CoreWCF up to 1.8.0/1.9.0 UnixPosixIdentitySecurityUpgradeProvider improper authentication

CVSS Meta Temp Score
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CTI Interest Score
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4.1$0-$5k0.00

Summaryinfo

A vulnerability marked as problematic has been reported in CoreWCF up to 1.8.0/1.9.0. Affected by this issue is some unknown functionality of the component UnixPosixIdentitySecurityUpgradeProvider. This manipulation causes improper authentication. The identification of this vulnerability is CVE-2026-54776. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in CoreWCF up to 1.8.0/1.9.0 and classified as problematic. Affected by this vulnerability is an unknown code of the component UnixPosixIdentitySecurityUpgradeProvider. The manipulation with an unknown input leads to a improper authentication vulnerability. The CWE definition for the vulnerability is CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. As an impact it is known to affect confidentiality. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-54776 since 06/16/2026. The exploitation appears to be easy. The attack can be launched remotely. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 1.8.1 or 1.9.1 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: CoreWCF 1.8.1/1.9.1

Timelineinfo

06/16/2026 CVE reserved
07/08/2026 +22 days VulDB entry created
07/09/2026 +0 days Advisory disclosed
07/09/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-54776 (🔒)
GCVE (CVE): GCVE-0-2026-54776
GCVE (VulDB): GCVE-100-377059

Entryinfo

Created: 07/09/2026 00:58
Changes: 07/09/2026 00:58 (52)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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