diff --git a/builtin/mailinfo.c b/builtin/mailinfo.c
index addc0e00a6..1566c19b62 100644
--- a/builtin/mailinfo.c
+++ b/builtin/mailinfo.c
@@ -185,7 +185,7 @@ static void handle_content_type(struct strbuf *line)
 
 	if (slurp_attr(line->buf, "boundary=", boundary)) {
 		strbuf_insert(boundary, 0, "--", 2);
-		if (++content_top > &content[MAX_BOUNDARIES]) {
+		if (++content_top >= &content[MAX_BOUNDARIES]) {
 			fprintf(stderr, "Too many boundaries to handle\n");
 			exit(1);
 		}