diff --git a/remote-curl.c b/remote-curl.c
index b5be25ce96..8ac5028343 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -227,6 +227,8 @@ static struct ref *parse_info_refs(struct discovery *heads)
 		if (data[i] == '\t')
 			mid = &data[i];
 		if (data[i] == '\n') {
+			if (mid - start != 40)
+				die("%sinfo/refs not valid: is this a git repository?", url);
 			data[i] = 0;
 			ref_name = mid + 1;
 			ref = xmalloc(sizeof(struct ref) +