diff --git a/libavformat/electronicarts.c b/libavformat/electronicarts.c
index fe19e70..ad63c56 100644
--- a/libavformat/electronicarts.c
+++ b/libavformat/electronicarts.c
@@ -448,12 +448,17 @@
 
     while (!packet_read) {
         chunk_type = get_le32(pb);
-        chunk_size = (ea->big_endian ? get_be32(pb) : get_le32(pb)) - 8;
+        chunk_size = ea->big_endian ? get_be32(pb) : get_le32(pb);
+        if (chunk_size <= 8)
+            return AVERROR_INVALIDDATA;
+        chunk_size -= 8;
 
         switch (chunk_type) {
         /* audio data */
         case ISNh_TAG:
             /* header chunk also contains data; skip over the header portion*/
+            if (chunk_size < 32)
+                return AVERROR_INVALIDDATA;
             url_fskip(pb, 32);
             chunk_size -= 32;
         case ISNd_TAG: