CVE-2026-54777

CoreWCF.NetNamedPipe transport is vulnerable to a local TOCTOU race where an attacker can race a NamedPipeListener between the shared-memory GUID publication and the creation of the service pipe, enabling interception of NetNamedPipe traffic by attaching to a pre-existing named pipe instance. Aff...

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

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 NamedPipeListen...

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

Impact CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance, allowing local interception of NetNamedPipe traffic. NetNamedPipe creates a shared memory object based on the listening url, then generated a unique GUID for the named pipe it will be using and saves this ...