diff --git a/pkgs/development/python-modules/cryptoparser/default.nix b/pkgs/development/python-modules/cryptoparser/default.nix
index 11425b4022ed..3535b79d30d1 100644
--- a/pkgs/development/python-modules/cryptoparser/default.nix
+++ b/pkgs/development/python-modules/cryptoparser/default.nix
@@ -24,6 +24,11 @@ buildPythonPackage rec {
     hash = "sha256-bEvhMVcm9sXlfhxUD2K4N10nusgxpGYFJQLtJE1/qok=";
   };
 
+  patches = [
+    # https://gitlab.com/coroner/cryptoparser/-/merge_requests/2
+    ./fix-dirs-exclude.patch
+  ];
+
   build-system = [
     setuptools
     setuptools-scm
@@ -37,6 +42,14 @@ buildPythonPackage rec {
     urllib3
   ];
 
+  postInstall = ''
+    find $out -name "__pycache__" -type d | xargs rm -rv
+
+    # Prevent creating more binary byte code later (e.g. during
+    # pythonImportsCheck)
+    export PYTHONDONTWRITEBYTECODE=1
+  '';
+
   pythonImportsCheck = [ "cryptoparser" ];
 
   meta = with lib; {
diff --git a/pkgs/development/python-modules/cryptoparser/fix-dirs-exclude.patch b/pkgs/development/python-modules/cryptoparser/fix-dirs-exclude.patch
new file mode 100644
index 000000000000..c667b3b1a8e5
--- /dev/null
+++ b/pkgs/development/python-modules/cryptoparser/fix-dirs-exclude.patch
@@ -0,0 +1,27 @@
+From 512b5d6e30784594db46bcd0071d63da7065e478 Mon Sep 17 00:00:00 2001
+From: Ivan Mincik <ivan.mincik@gmail.com>
+Date: Wed, 17 Sep 2025 14:09:31 +0200
+Subject: [PATCH] Fix directories exclude from package
+
+* correctly exclude submodules directory
+* also exclude docs directory
+---
+ pyproject.toml | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/pyproject.toml b/pyproject.toml
+index 73897d6..74d43e4 100644
+--- a/pyproject.toml
++++ b/pyproject.toml
+@@ -75,7 +75,7 @@ technical_name = 'cryptoparser'
+ license-files = ['LICENSE.txt']
+ 
+ [tool.setuptools.packages.find]
+-exclude = ['submodules']
++exclude = ['submodules*', 'docs']
+ 
+ [tool.tox]
+ envlist = [
+-- 
+GitLab
+