diff --git a/remote-curl.c b/remote-curl.c
index 0053b09549ab419ab8f2da2c519d689f5e0d83b3..99030774713221d605a2731ca2f3fa46d9115631 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -339,6 +339,8 @@ static struct discovery *discover_refs(const char *service, int for_push)
 		 * pkt-line matches our request.
 		 */
 		line = packet_read_line_buf(&last->buf, &last->len, NULL);
+		if (!line)
+			die("invalid server response; expected service, got flush packet");
 
 		strbuf_reset(&exp);
 		strbuf_addf(&exp, "# service=%s", service);
diff --git a/send-pack.c b/send-pack.c
index 2112d3b27ad21e1d457b08a3aa71a811b5e8ee79..8d9190f5e7815c6b2f18afd266643a8c862e526e 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -137,6 +137,8 @@ static int pack_objects(int fd, struct ref *refs, struct oid_array *extra, struc
 static int receive_unpack_status(int in)
 {
 	const char *line = packet_read_line(in, NULL);
+	if (!line)
+		return error(_("unexpected flush packet while reading remote unpack status"));
 	if (!skip_prefix(line, "unpack ", &line))
 		return error(_("unable to parse remote unpack status: %s"), line);
 	if (strcmp(line, "ok"))