--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -737,7 +737,15 @@ ngx_http_fastcgi_create_request(ngx_http
         lowcase_key = NULL;
 
         if (flcf->header_params) {
-            ignored = ngx_palloc(r->pool, flcf->header_params * sizeof(void *));
+            n = 0;
+            part = &r->headers_in.headers.part;
+
+            while (part) {
+                n += part->nelts;
+                part = part->next;
+            }
+
+            ignored = ngx_palloc(r->pool, n * sizeof(void *));
             if (ignored == NULL) {
                 return NGX_ERROR;
             }

--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -561,7 +561,15 @@ ngx_http_scgi_create_request(ngx_http_re
         lowcase_key = NULL;
 
         if (scf->header_params) {
-            ignored = ngx_palloc(r->pool, scf->header_params * sizeof(void *));
+            n = 0;
+            part = &r->headers_in.headers.part;
+
+            while (part) {
+                n += part->nelts;
+                part = part->next;
+            }
+
+            ignored = ngx_palloc(r->pool, n * sizeof(void *));
             if (ignored == NULL) {
                 return NGX_ERROR;
             }

--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -589,7 +589,15 @@ ngx_http_uwsgi_create_request(ngx_http_r
         lowcase_key = NULL;
 
         if (uwcf->header_params) {
-            ignored = ngx_palloc(r->pool, uwcf->header_params * sizeof(void *));
+            n = 0;
+            part = &r->headers_in.headers.part;
+
+            while (part) {
+                n += part->nelts;
+                part = part->next;
+            }
+
+            ignored = ngx_palloc(r->pool, n * sizeof(void *));
             if (ignored == NULL) {
                 return NGX_ERROR;
             }