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Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M

CVE-2026-54777CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance

Medium 6.5

In plain English

A medium-severity security flaw in CoreWCF from CoreWCF. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.1%top 98.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
NuGetcorewcf.netnamedpipe1.8.1GHSA-6jj2-4q5c-x8g6
NuGetcorewcf.netnamedpipe1.9.1GHSA-6jj2-4q5c-x8g6

Affected products (as reported)

VendorProductVersions
CoreWCF CoreWCF >= 1.9.0, < 1.9.1< 1.8.1

Weakness: CWE-367, CWE-665 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L

References