diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 6cc770b1ea..75e7035b8a 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -694,6 +694,11 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
         ret = AVERROR(EINVAL);
         goto free_and_end;
     }
+    if (avctx->block_align < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid block align: %d\n", avctx->block_align);
+        ret = AVERROR(EINVAL);
+        goto free_and_end;
+    }
 
     avctx->codec = codec;
     if ((avctx->codec_type == AVMEDIA_TYPE_UNKNOWN || avctx->codec_type == codec->type) &&