# CVE-2026-54777

## Summary

- **CVE ID:** CVE-2026-54777
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L)
- **CWE:** CWE-367, CWE-665
- **Published:** Jul 8, 2026
- **Last Modified:** Jul 10, 2026

## 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, 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.

## Affected Products

- CoreWCF — CoreWCF (>= 1.9.0, < 1.9.1)
- CoreWCF — CoreWCF (< 1.8.1)

## References

- [CNA](https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-6jj2-4q5c-x8g6)
- [CNA](https://github.com/CoreWCF/CoreWCF/commit/8ed9c780c7c6fb22fa215c5771dee0c1e49596b7)
- [CNA](https://github.com/CoreWCF/CoreWCF/commit/e7d225394fd429900dcbc445dcdd53b94e964077)
- [CNA](https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1)
- [CNA](https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.12%
- **EPSS Percentile:** 1.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._