diff --git a/src/http/ngx_http_parse.c b/src/http/ngx_http_parse.c
index 752b6a1..027d9ef 100644
--- a/src/http/ngx_http_parse.c
+++ b/src/http/ngx_http_parse.c
@@ -529,6 +529,8 @@
 
         /* first char */
         case sw_start:
+            r->invalid_header = 0;
+
             switch (ch) {
             case CR:
                 r->header_end = p;
@@ -552,6 +554,8 @@
                     break;
                 }
 
+                r->invalid_header = 1;
+
                 break;
 
             }
@@ -606,6 +610,8 @@
                 break;
             }
 
+            r->invalid_header = 1;
+
             break;
 
         /* space* before header value */