diff --git a/libavformat/asfdec_o.c b/libavformat/asfdec_o.c
index e837ca62e7..2b407c016f 100644
--- a/libavformat/asfdec_o.c
+++ b/libavformat/asfdec_o.c
@@ -888,6 +888,8 @@ static int asf_read_simple_index(AVFormatContext *s, const GUIDParseTable *g)
             av_log(s, AV_LOG_ERROR, "Skipping failed in asf_read_simple_index.\n");
             return offset;
         }
+        if (asf->first_packet_offset > INT64_MAX - asf->packet_size * pkt_num)
+            return AVERROR_INVALIDDATA;
         if (prev_pkt_num != pkt_num) {
             av_add_index_entry(st, asf->first_packet_offset + asf->packet_size *
                                pkt_num, av_rescale(interval, i, 10000),