diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c
index 535139e703..4513287ef9 100644
--- a/libavcodec/cbs_av1.c
+++ b/libavcodec/cbs_av1.c
@@ -1071,8 +1071,12 @@ static int cbs_av1_read_unit(CodedBitstreamContext *ctx,
     if (obu->obu_size > 0 &&
         obu->header.obu_type != AV1_OBU_TILE_GROUP &&
         obu->header.obu_type != AV1_OBU_FRAME) {
-        err = cbs_av1_read_trailing_bits(ctx, &gbc,
-                                         obu->obu_size * 8 + start_pos - end_pos);
+        int nb_bits = obu->obu_size * 8 + start_pos - end_pos;
+
+        if (nb_bits <= 0)
+            return AVERROR_INVALIDDATA;
+
+        err = cbs_av1_read_trailing_bits(ctx, &gbc, nb_bits);
         if (err < 0)
             return err;
     }