Fix issue that could lead to RCE if using unsecure Jinja templates in…

… dynamic prompt builders (#8096)

haystack/components/builders/dynamic_chat_prompt_builder.py

@@ -5,7 +5,8 @@
 import warnings
 from typing import Any, Dict, List, Optional, Set
 
-from jinja2 import Template, meta
+from jinja2 import meta
+from jinja2.sandbox import SandboxedEnvironment
 
 from haystack import component, logging
 from haystack.dataclasses.chat_message import ChatMessage, ChatRole
@@ -177,8 +178,8 @@ def _validate_template(self, template_text: str, provided_variables: Set[str]):
         :raises ValueError:
             If all the required template variables are not provided.
         """
-        template = Template(template_text)
-        ast = template.environment.parse(template_text)
+        env = SandboxedEnvironment()
+        ast = env.parse(template_text)
         required_template_variables = meta.find_undeclared_variables(ast)
         filled_template_vars = required_template_variables.intersection(provided_variables)
         if len(filled_template_vars) != len(required_template_variables):
@@ -187,4 +188,4 @@ def _validate_template(self, template_text: str, provided_variables: Set[str]):
                 f"Required variables: {required_template_variables}. Only the following variables were "
                 f"provided: {provided_variables}. Please provide all the required template variables."
             )
-        return template
+        return env.from_string(template_text)

haystack/components/builders/dynamic_prompt_builder.py

@@ -5,7 +5,8 @@
 import warnings
 from typing import Any, Dict, List, Optional, Set
 
-from jinja2 import Template, meta
+from jinja2 import meta
+from jinja2.sandbox import SandboxedEnvironment
 
 from haystack import component, logging
 
@@ -156,8 +157,8 @@ def _validate_template(self, template_text: str, provided_variables: Set[str]):
         :raises ValueError:
             If all the required template variables are not provided.
         """
-        template = Template(template_text)
-        ast = template.environment.parse(template_text)
+        env = SandboxedEnvironment()
+        ast = env.parse(template_text)
         required_template_variables = meta.find_undeclared_variables(ast)
         filled_template_vars = required_template_variables.intersection(provided_variables)
         if len(filled_template_vars) != len(required_template_variables):
@@ -166,4 +167,4 @@ def _validate_template(self, template_text: str, provided_variables: Set[str]):
                 f"Required variables: {required_template_variables}. Only the following variables were "
                 f"provided: {provided_variables}. Please provide all the required template variables."
             )
-        return template
+        return env.from_string(template_text)

releasenotes/notes/fix-jinja-env-81c98225b22dc827.yaml

@@ -8,6 +8,8 @@ security:
 
     - `PromptBuilder`
     - `ChatPromptBuilder`
+    - `DynamicPromptBuilder`
+    - `DynamicChatPromptBuilder`
     - `OutputAdapter`
     - `ConditionalRouter`