diff --git a/Source/NSMessagePortNameServer.m b/Source/NSMessagePortNameServer.m
index 8984f9361..d4d9174ff 100644
--- a/Source/NSMessagePortNameServer.m
+++ b/Source/NSMessagePortNameServer.m
@@ -363,7 +363,7 @@ static NSMapTable *portToNamesMap;
 
       memset(&sockAddr, '\0', sizeof(sockAddr));
       sockAddr.sun_family = AF_LOCAL;
-      strncpy(sockAddr.sun_path, socket_path, sizeof(sockAddr.sun_path));
+      strncpy(sockAddr.sun_path, socket_path, sizeof(sockAddr.sun_path) - 1);
 
       if ((desc = socket(PF_LOCAL, SOCK_STREAM, PF_UNSPEC)) < 0)
 	{