diff --git a/libavformat/asfdec_o.c b/libavformat/asfdec_o.c
index 3729adee2f..c1d90360b4 100644
--- a/libavformat/asfdec_o.c
+++ b/libavformat/asfdec_o.c
@@ -854,6 +854,8 @@ static int asf_read_ext_stream_properties(AVFormatContext *s, const GUIDParseTab
     st_num     = avio_rl16(pb);
     st_num    &= ASF_STREAM_NUM;
     lang_idx   = avio_rl16(pb); // Stream Language ID Index
+    if (lang_idx >= ASF_MAX_STREAMS)
+        return AVERROR_INVALIDDATA;
     for (i = 0; i < asf->nb_streams; i++) {
         if (st_num == asf->asf_st[i]->stream_index) {
             st                       = s->streams[asf->asf_st[i]->index];