Threats affecting pkg:pypi/langgraph-checkpoint

A deserialization vulnerability (CWE-502) exists in langchain-ai's langgraph-checkpoint versions prior to 4.0.0. The issue arises when applications explicitly enable caching with cache backends inheriting from BaseCache and nodes opt into caching via CachePolicy. The default serializer falls back to pickle.loads for certain data, allowing remote code execution if an attacker can write malicious serialized data into the cache backend. Exploitation requires write access to the cache storage, making this a post-compromise escalation vector. The vulnerability is patched in langgraph-checkpoint version 4.0.0.