diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index eb1db615ae..19bac949d4 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -184,8 +184,8 @@ static av_cold int decode_init(AVCodecContext *avctx)
     unsigned int channel_mask;
     int i, log2_max_num_subframes;
 
-    if (!avctx->block_align) {
-        av_log(avctx, AV_LOG_ERROR, "block_align is not set\n");
+    if (avctx->block_align <= 0) {
+        av_log(avctx, AV_LOG_ERROR, "block_align is not set or invalid\n");
         return AVERROR(EINVAL);
     }