## Summary - Removes the `xslt_path` parameter from HTMLSectionSplitter to eliminate XXE attack vector - Hardens XML/HTML parsers with secure configurations to prevent XXE attacks - Adds comprehensive security tests to ensure the vulnerability is fixed ## Context This PR addresses a critical XXE vulnerability discovered in the HTMLSectionSplitter component. The vulnerability allowed attackers to: - Read sensitive local files (SSH keys, passwords, configuration files) - Perform Server-Side Request Forgery (SSRF) attacks - Exfiltrate data to attacker-controlled servers ## Changes Made 1. **Removed `xslt_path` parameter** - This eliminates the primary attack vector where users could supply malicious XSLT files 2. **Hardened XML parsers** - Added security configurations to prevent XXE attacks even with the default XSLT: - `no_network=True` - Blocks network access - `resolve_entities=False` - Prevents entity expansion - `load_dtd=False` - Disables DTD processing - `XSLTAccessControl.DENY_ALL` - Blocks all file/network I/O in XSLT transformations 3. **Added security tests** - New test file `test_html_security.py` with comprehensive tests for various XXE attack vectors 4. **Updated existing tests** - Modified tests that were using the removed `xslt_path` parameter ## Test Plan - [x] All existing tests pass - [x] New security tests verify XXE attacks are blocked - [x] Code passes linting and formatting checks - [x] Tested with both old and new versions of lxml Twitter handle: @_colemurray |
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Note
Looking for the JS/TS library? Check out LangChain.js.
LangChain is a framework for building LLM-powered applications. It helps you chain together interoperable components and third-party integrations to simplify AI application development — all while future-proofing decisions as the underlying technology evolves.
pip install -U langchain
To learn more about LangChain, check out the docs. If you’re looking for more advanced customization or agent orchestration, check out LangGraph, our framework for building controllable agent workflows.
Why use LangChain?
LangChain helps developers build applications powered by LLMs through a standard interface for models, embeddings, vector stores, and more.
Use LangChain for:
- Real-time data augmentation. Easily connect LLMs to diverse data sources and external / internal systems, drawing from LangChain’s vast library of integrations with model providers, tools, vector stores, retrievers, and more.
- Model interoperability. Swap models in and out as your engineering team experiments to find the best choice for your application’s needs. As the industry frontier evolves, adapt quickly — LangChain’s abstractions keep you moving without losing momentum.
LangChain’s ecosystem
While the LangChain framework can be used standalone, it also integrates seamlessly with any LangChain product, giving developers a full suite of tools when building LLM applications.
To improve your LLM application development, pair LangChain with:
- LangSmith - Helpful for agent evals and observability. Debug poor-performing LLM app runs, evaluate agent trajectories, gain visibility in production, and improve performance over time.
- LangGraph - Build agents that can reliably handle complex tasks with LangGraph, our low-level agent orchestration framework. LangGraph offers customizable architecture, long-term memory, and human-in-the-loop workflows — and is trusted in production by companies like LinkedIn, Uber, Klarna, and GitLab.
- LangGraph Platform - Deploy and scale agents effortlessly with a purpose-built deployment platform for long running, stateful workflows. Discover, reuse, configure, and share agents across teams — and iterate quickly with visual prototyping in LangGraph Studio.
Additional resources
- Tutorials: Simple walkthroughs with guided examples on getting started with LangChain.
- How-to Guides: Quick, actionable code snippets for topics such as tool calling, RAG use cases, and more.
- Conceptual Guides: Explanations of key concepts behind the LangChain framework.
- API Reference: Detailed reference on navigating base packages and integrations for LangChain.