--- a/src/mail/ngx_mail_imap_module.c
+++ b/src/mail/ngx_mail_imap_module.c
@@ -184,7 +184,7 @@ ngx_mail_imap_merge_srv_conf(ngx_conf_t 
         }
     }
 
-    p = ngx_palloc(cf->pool, size);
+    p = ngx_pnalloc(cf->pool, size);
     if (p == NULL) {
         return NGX_CONF_ERROR;
     }
@@ -217,7 +217,7 @@ ngx_mail_imap_merge_srv_conf(ngx_conf_t 
 
     size += sizeof(" STARTTLS") - 1;
 
-    p = ngx_palloc(cf->pool, size);
+    p = ngx_pnalloc(cf->pool, size);
     if (p == NULL) {
         return NGX_CONF_ERROR;
     }
@@ -234,7 +234,7 @@ ngx_mail_imap_merge_srv_conf(ngx_conf_t 
     size = (auth - conf->capability.data) + sizeof(CRLF) - 1
             + sizeof(" STARTTLS LOGINDISABLED") - 1;
 
-    p = ngx_palloc(cf->pool, size);
+    p = ngx_pnalloc(cf->pool, size);
     if (p == NULL) {
         return NGX_CONF_ERROR;
     }