diff --git a/pkgs/by-name/dm/dmarc-metrics-exporter/package.nix b/pkgs/by-name/dm/dmarc-metrics-exporter/package.nix
index 369dd3548d36..106f398c06b0 100644
--- a/pkgs/by-name/dm/dmarc-metrics-exporter/package.nix
+++ b/pkgs/by-name/dm/dmarc-metrics-exporter/package.nix
@@ -1,10 +1,15 @@
 {
   lib,
   stdenv,
-  python3,
+  python312,
   fetchFromGitHub,
 }:
 
+let
+  # more-itertools unsupported on 3.13
+  python3 = python312;
+in
+
 python3.pkgs.buildPythonApplication rec {
   pname = "dmarc-metrics-exporter";
   version = "1.2.0";