diff --git a/src/hlua.c b/src/hlua.c
index cefaf38..37f7866 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -3911,7 +3911,7 @@
 
 	htx = htxbuf(&s->req.buf);
 	blk = htx_get_first_blk(htx);
-	BUG_ON(htx_get_blk_type(blk) != HTX_BLK_REQ_SL);
+	BUG_ON(!blk || htx_get_blk_type(blk) != HTX_BLK_REQ_SL);
 	sl = htx_get_blk_ptr(htx, blk);
 
 	/* Stores the request method. */
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 49e0a2f..2454345 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -4629,7 +4629,7 @@
 
 	/* get the start line, we do have one */
 	blk = htx_get_head_blk(htx);
-	BUG_ON(htx_get_blk_type(blk) != HTX_BLK_RES_SL);
+	BUG_ON(!blk || htx_get_blk_type(blk) != HTX_BLK_RES_SL);
 	ALREADY_CHECKED(blk);
 	sl = htx_get_blk_ptr(htx, blk);
 	h2s->status = sl->info.res.status;
@@ -4864,7 +4864,7 @@
 
 	/* get the start line, we do have one */
 	blk = htx_get_head_blk(htx);
-	BUG_ON(htx_get_blk_type(blk) != HTX_BLK_REQ_SL);
+	BUG_ON(!blk || htx_get_blk_type(blk) != HTX_BLK_REQ_SL);
 	ALREADY_CHECKED(blk);
 	sl = htx_get_blk_ptr(htx, blk);
 	meth = htx_sl_req_meth(sl);
diff --git a/src/stats.c b/src/stats.c
index 02057c5..5954fe6 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -284,7 +284,7 @@
 	struct ist uri;
 
 	blk = htx_get_head_blk(htx);
-	BUG_ON(htx_get_blk_type(blk) != HTX_BLK_REQ_SL);
+	BUG_ON(!blk || htx_get_blk_type(blk) != HTX_BLK_REQ_SL);
 	ALREADY_CHECKED(blk);
 	uri = htx_sl_req_uri(htx_get_blk_ptr(htx, blk));
 	return uri.ptr + appctx->ctx.stats.scope_str;