diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index 58aa65aeb1..4470ee02a2 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -839,6 +839,9 @@ static int cbs_h264_read_nal_unit(CodedBitstreamContext *ctx,
             if (err < 0)
                 return err;
 
+            if (!cbs_h2645_read_more_rbsp_data(&gbc))
+                return AVERROR_INVALIDDATA;
+
             pos = get_bits_count(&gbc);
             len = unit->data_size;
 
@@ -1014,6 +1017,9 @@ static int cbs_h265_read_nal_unit(CodedBitstreamContext *ctx,
             if (err < 0)
                 return err;
 
+            if (!cbs_h2645_read_more_rbsp_data(&gbc))
+                return AVERROR_INVALIDDATA;
+
             pos = get_bits_count(&gbc);
             len = unit->data_size;