diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 544fd74..e579fb5 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2031,7 +2031,7 @@
         return NGX_DECLINED;
     }
 
-    if (ae->value.len < 5) {
+    if (ae->value.len < sizeof("gzip") - 1) {
         return NGX_DECLINED;
     }