diff --git a/libavcodec/atrac9dec.c b/libavcodec/atrac9dec.c
index e3e4f2f14e..5415d1348e 100644
--- a/libavcodec/atrac9dec.c
+++ b/libavcodec/atrac9dec.c
@@ -199,7 +199,7 @@ static inline int parse_band_ext(ATRAC9Context *s, ATRAC9BlockData *b,
     int ext_band = 0;
 
     if (b->has_band_ext) {
-        if (b->q_unit_cnt < 13)
+        if (b->q_unit_cnt < 13 || b->q_unit_cnt > 20)
             return AVERROR_INVALIDDATA;
         ext_band = at9_tab_band_ext_group[b->q_unit_cnt - 13][2];
         if (stereo) {