diff --git a/libavformat/mov.c b/libavformat/mov.c
index 55bafaa26a..20b6ef3dac 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -6754,6 +6754,9 @@ static int mov_read_saiz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     sample_count = avio_rb32(pb);
 
     if (encryption_index->auxiliary_info_default_size == 0) {
+        if (sample_count == 0)
+            return AVERROR_INVALIDDATA;
+
         encryption_index->auxiliary_info_sizes = av_malloc(sample_count);
         if (!encryption_index->auxiliary_info_sizes)
             return AVERROR(ENOMEM);