CVE-2026-34070 Details

A directory traversal vulnerability has been identified in LangChain versions prior to 1.2.22. The issue arises in multiple functions within the 'langchain_core.prompts.loading' module, which read files from paths embedded in deserialized configuration dictionaries. These functions do not validate the paths against directory traversal or absolute path injection, allowing attackers to read arbitrary files from the host filesystem. The vulnerability is constrained by file-extension checks, permitting only certain types of files to be accessed. This issue affects applications that pass user-influenced prompt configurations to the 'load_prompt()' or 'load_prompt_from_config()' functions.'

Users are advised to update LangChain to version 1.2.22 or later. The updated version includes path validation that rejects absolute paths and directory traversal sequences. For applications that require loading prompts from configurations that may contain such paths, the 'allow_dangerous_paths=True' option can be used, but with caution.