diff --git a/libs/sofia-sip/libsofia-sip-ua/msg/msg_parser_util.c b/libs/sofia-sip/libsofia-sip-ua/msg/msg_parser_util.c
index 11fc1358eb..b64c4489df 100644
--- a/libs/sofia-sip/libsofia-sip-ua/msg/msg_parser_util.c
+++ b/libs/sofia-sip/libsofia-sip-ua/msg/msg_parser_util.c
@@ -1762,7 +1762,7 @@ issize_t msg_unquoted_e(char *b, isize_t bsiz, char const *s)
       s++;
     }
     else {
-      if (e + n <= bsiz)
+      if (b && (e + n <= bsiz))
 	memcpy(b + e, s, n);
       e += n;
       s += n;