From 45c726fd4daa63236a8f3653530f297dc87b160a Mon Sep 17 00:00:00 2001
From: Eric Soroos <eric-github@soroos.net>
Date: Fri, 27 Oct 2023 11:21:18 +0200
Subject: [PATCH] Don't allow __ or builtins in env dictionarys for
 ImageMath.eval

---
 src/PIL/ImageMath.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/PIL/ImageMath.py b/src/PIL/ImageMath.py
index 7ca512e75..cf108e258 100644
--- a/src/PIL/ImageMath.py
+++ b/src/PIL/ImageMath.py
@@ -237,6 +237,10 @@ def eval(expression, _dict={}, **kw):
     args.update(_dict)
     args.update(kw)
     for k, v in args.items():
+        if '__' in k or hasattr(__builtins__, k):
+            msg = f"'{k}' not allowed"
+            raise ValueError(msg)
+
         if hasattr(v, "im"):
             args[k] = _Operand(v)