diff --git a/src/helper/binarybuffer.h b/src/helper/binarybuffer.h
index 103a48c5c..df4199837 100644
--- a/src/helper/binarybuffer.h
+++ b/src/helper/binarybuffer.h
@@ -34,6 +34,7 @@
 static inline void buf_set_u32(uint8_t *_buffer,
 	unsigned first, unsigned num, uint32_t value)
 {
+	assert(num >= 1 && num <= 32);
 	uint8_t *buffer = _buffer;
 
 	if ((num == 32) && (first == 0)) {
@@ -64,6 +65,7 @@ static inline void buf_set_u32(uint8_t *_buffer,
 static inline void buf_set_u64(uint8_t *_buffer,
 	unsigned first, unsigned num, uint64_t value)
 {
+	assert(num >= 1 && num <= 64);
 	uint8_t *buffer = _buffer;
 
 	if ((num == 32) && (first == 0)) {
@@ -102,6 +104,7 @@ static inline void buf_set_u64(uint8_t *_buffer,
 static inline uint32_t buf_get_u32(const uint8_t *_buffer,
 	unsigned first, unsigned num)
 {
+	assert(num >= 1 && num <= 32);
 	const uint8_t *buffer = _buffer;
 
 	if ((num == 32) && (first == 0)) {
@@ -131,6 +134,7 @@ static inline uint32_t buf_get_u32(const uint8_t *_buffer,
 static inline uint64_t buf_get_u64(const uint8_t *_buffer,
 	unsigned first, unsigned num)
 {
+	assert(num >= 1 && num <= 64);
 	const uint8_t *buffer = _buffer;
 
 	if ((num == 32) && (first == 0)) {