CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution

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.