diff --git a/sway/ipc-server.c b/sway/ipc-server.c
index 4d9264e8c..a9325a81b 100644
--- a/sway/ipc-server.c
+++ b/sway/ipc-server.c
@@ -66,6 +66,7 @@ void ipc_init(void) {
 	// We want to use socket name set by user, not existing socket from another sway instance.
 	if (getenv("SWAYSOCK") != NULL && access(getenv("SWAYSOCK"), F_OK) == -1) {
 		strncpy(ipc_sockaddr->sun_path, getenv("SWAYSOCK"), sizeof(ipc_sockaddr->sun_path));
+		ipc_sockaddr->sun_path[sizeof(ipc_sockaddr->sun_path) - 1] = 0;
 	}
 
 	unlink(ipc_sockaddr->sun_path);