diff --git a/sys/bus/pccard/pccard.c b/sys/bus/pccard/pccard.c
--- a/sys/bus/pccard/pccard.c
+++ b/sys/bus/pccard/pccard.c
@@ -996,6 +996,10 @@
 
 	if (len == 0)
 		return;
+	if (src == NULL) {
+		*walker = '\0';
+		return;
+	}
 	while (walker < ep)
 	{
 		if (*src == '"') {