diff --git a/pkgs/development/python-modules/karton-core/default.nix b/pkgs/development/python-modules/karton-core/default.nix
index 909c7b8031ac..ace43f0e7b08 100644
--- a/pkgs/development/python-modules/karton-core/default.nix
+++ b/pkgs/development/python-modules/karton-core/default.nix
@@ -9,16 +9,16 @@
   unittestCheckHook,
 }:
 
-buildPythonPackage rec {
+buildPythonPackage (finalAttrs: {
   pname = "karton-core";
-  version = "5.9.0";
+  version = "5.9.1";
   pyproject = true;
 
   src = fetchFromGitHub {
     owner = "CERT-Polska";
     repo = "karton";
-    tag = "v${version}";
-    hash = "sha256-m7A7Fbl6VZtgR4+FhmV2T+K6kgHRNtdeyin1uhvw04U=";
+    tag = "v${finalAttrs.version}";
+    hash = "sha256-b/wOkOk6LB8uTDsXJrNQ2iru2H6mgaMhIyWSU5y2mx0=";
   };
 
   build-system = [ setuptools ];
@@ -41,11 +41,11 @@ buildPythonPackage rec {
   meta = {
     description = "Distributed malware processing framework";
     homepage = "https://karton-core.readthedocs.io/";
-    changelog = "https://github.com/CERT-Polska/karton/releases/tag/${src.tag}";
+    changelog = "https://github.com/CERT-Polska/karton/releases/tag/${finalAttrs.src.tag}";
     license = lib.licenses.bsd3;
     maintainers = with lib.maintainers; [
       chivay
       fab
     ];
   };
-}
+})