CVE-2026-54778: Corewcf

Medium severity, CVSS 6.2. EPSS: 0.1% chance of exploitation in the next 30 days.

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 UnixDomainSocket POSIX peer identity resolution uses non-reentrant getpwuid and getgrgid calls, allowing concurrent connections to attribute one connection's identity to another or crash the host process under contention. This issue is fixed in versions 1.8.1 and 1.9.1.

Affected products

• Corewcf Corewcf: from 1.9.0, before 1.9.1 (fixed in 1.9.1); before 1.8.1 (fixed in 1.8.1)

Published 2026-07-08. Last modified 2026-07-09.