diff --git a/libr/anal/flirt.c b/libr/anal/flirt.c
index 5eb061bd07411..3d258fd6d2dcc 100644
--- a/libr/anal/flirt.c
+++ b/libr/anal/flirt.c
@@ -1349,6 +1349,7 @@ static RFlirtNode *flirt_parse(RFlirt *f) {
 
 // if buf is a flirt signature, returns signature version, or zero
 R_API int r_sign_is_flirt(RBuffer *buf) {
+	R_RETURN_VAL_IF_FAIL (buf, 0);
 	int ret = 0;
 	idasig_v5_t *header = R_NEW0 (idasig_v5_t);
 	if (!header) {