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CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution

Moderate severity GitHub Reviewed Published Jun 16, 2026 in CoreWCF/CoreWCF • Updated Jun 19, 2026

Package

nuget CoreWCF.UnixDomainSocket (NuGet)

Affected versions

< 1.8.1
>= 1.9.0, < 1.9.1

Patched versions

1.8.1
1.9.1

Description

Impact

Race condition in POSIX peer identity resolution may attribute one connection’s identity to another (getpwuid/getgrgid non-reentrant) and may crash the host process under contention.

Patches

Fixed in CoreWCF v1.8.1 and v1.9.1

Workarounds

Restrict UDS filesystem permissions so that only trusted local users can connect to the socket path. The race still exists but the attacker pool is constrained.

References

@mconnew mconnew published to CoreWCF/CoreWCF Jun 16, 2026
Published to the GitHub Advisory Database Jun 19, 2026
Reviewed Jun 19, 2026
Last updated Jun 19, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(1st percentile)

Weaknesses

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. Learn more on MITRE.

Expired Pointer Dereference

The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid. Learn more on MITRE.

CVE ID

CVE-2026-54778

GHSA ID

GHSA-q6v9-43v5-jv9q

Source code

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