diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
index 972271e2e9..e8b95c56eb 100644
--- a/libavcodec/alsdec.c
+++ b/libavcodec/alsdec.c
@@ -1012,6 +1012,10 @@ static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
     GetBitContext *gb        = &ctx->gb;
 
     *bd->shift_lsbs = 0;
+
+    if (get_bits_left(gb) < 1)
+        return AVERROR_INVALIDDATA;
+
     // read block type flag and read the samples accordingly
     if (get_bits1(gb)) {
         ret = read_var_block_data(ctx, bd);