diff --git a/mozilla/mailnews/addrbook/src/nsVCardObj.cpp b/mozilla/mailnews/addrbook/src/nsVCardObj.cpp
index 3f767cc0fc1..ead3e002426 100644
--- a/mozilla/mailnews/addrbook/src/nsVCardObj.cpp
+++ b/mozilla/mailnews/addrbook/src/nsVCardObj.cpp
@@ -1344,16 +1344,13 @@ static void writeAttrValue(OFile *fp, VObject *o, int* length)
 
 static void writeGroup(OFile *fp, VObject *o)
 {
-    char buf1[256];
-    char buf2[256];
-    PL_strcpy(buf1,NAME_OF(o));
-    while ((o=isAPropertyOf(o,VCGroupingProp)) != 0) {
-  PL_strcpy(buf2,STRINGZ_VALUE_OF(o));
-  PL_strcat(buf2,".");
-  PL_strcat(buf2,buf1);
-  PL_strcpy(buf1,buf2);
+  nsCAutoString buf(NAME_OF(o));
+
+  while ((o=isAPropertyOf(o,VCGroupingProp)) != 0) {
+    buf.Insert(NS_LITERAL_CSTRING("."), 0);
+    buf.Insert(STRINGZ_VALUE_OF(o), 0);
   }
-    appendsOFile(fp,buf1);
+  appendsOFile(fp, buf.get());
 }
 
 static int inList(const char **list, const char *s)