Submit #410043: langflow-ai langflow <=v1.0.18 Redos

The following code in `langflow-1.0.18\src\backend\base\langflow\interface\utils.py` could lead to a ReDoS (Regular Expression Denial of Service) attack:

```
pattern = r"\{\{(.*?)\}\}|\{([^{}]+)\}"

  while True:
      match = re.search(pattern, remaining_text)
```

`remaining_text` is the `prompt_request.template` parameter transmitted by the user via a POST method:

```
@router.post("/prompt", status_code=200, response_model=PromptValidationResponse)
def post_validate_prompt(prompt_request: ValidatePromptRequest):
  try:
      if not prompt_request.frontend_node:
          return PromptValidationResponse(
              input_variables=[],
              frontend_node=None,
          )

      # Process the prompt template using direct attributes
      input_variables = process_prompt_template(
          template=prompt_request.template,
          name=prompt_request.name,
          custom_fields=prompt_request.frontend_node.custom_fields,
          frontend_node_template=prompt_request.frontend_node.template,
      )

      return PromptValidationResponse(
          input_variables=input_variables,
          frontend_node=prompt_request.frontend_node,
      )
  except Exception as e:
      logger.exception(e)
      raise HTTPException(status_code=500, detail=str(e)) from e
```

• Source: ⚠️ https://rumbling-slice-eb0.notion.site/Remote-Redos-in-https-github-com-langflow-ai-langflow-067159ced0d5494e91b06071384969c4?pvs=4
• User: HRP_0 (UID 75007)
• Submission: 09/18/2024 07:38 (2 years ago)
• Moderation: 09/27/2024 07:32 (9 days later)
• Status: Accepted
• VulDB entry: 278659 [Langflow up to 1.0.18 HTTP POST Request utils.py remaining_text redos]
• Points: 17