diff --git a/default.nix b/default.nix
index ac75bce..8eb9c5b 100644
--- a/default.nix
+++ b/default.nix
@@ -460,6 +460,22 @@ in
       '';
     };
 
+    lmtpMemoryLimit = mkOption {
+      type = types.int;
+      default = 256;
+      description = ''
+        The memory limit for the LMTP service, in megabytes.
+      '';
+    };
+
+    quotaStatusMemoryLimit = mkOption {
+      type = types.int;
+      default = 256;
+      description = ''
+        The memory limit for the quota-status service, in megabytes.
+      '';
+    };
+
     extraVirtualAliases = mkOption {
       type = let
         loginAccount = mkOptionType {
@@ -696,6 +712,14 @@ in
       '';
     };
 
+    imapMemoryLimit = mkOption {
+      type = types.int;
+      default = 256;
+      description = ''
+        The memory limit for the imap service, in megabytes.
+      '';
+    };
+
     enableImapSsl = mkOption {
       type = types.bool;
       default = true;
diff --git a/mail-server/dovecot.nix b/mail-server/dovecot.nix
index 11f2708..6e39923 100644
--- a/mail-server/dovecot.nix
+++ b/mail-server/dovecot.nix
@@ -276,6 +276,10 @@ in
           mail_plugins = $mail_plugins imap_sieve
         }
 
+        service imap {
+	  vsz_limit = ${builtins.toString cfg.imapMemoryLimit} MB
+	}
+
         protocol pop3 {
           mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
         }
@@ -291,8 +295,13 @@ in
             mode = 0600
             user = ${postfixCfg.user}
           }
+	  vsz_limit = ${builtins.toString cfg.lmtpMemoryLimit} MB
         }
 
+        service quota-status {
+	  vsz_limit = ${builtins.toString cfg.quotaStatusMemoryLimit} MB
+	}
+
         recipient_delimiter = ${cfg.recipientDelimiter}
         lmtp_save_to_detail_mailbox = ${cfg.lmtpSaveToDetailMailbox}