CVE-2026-44843
LangChain vulnerable to unsafe deserialization of attacker-controlled objects through overly broad `load()` allowlists
Impact
LangChain is a framework for building agents and LLM-powered applications. Prior to 0.3.85 and 1.3.3, LangChain contains older runtime code paths that deserialize run inputs, run outputs, or other application-controlled payloads using overly broad object allowlists. These paths may call load() with allowed_objects="all". This does not enable arbitrary Python object deserialization, but it does allow any trusted LangChain-serializable object to be revived, which is broader than these runtime paths require. As a result, attacker-supplied LangChain serialized constructor dictionaries may cause trusted runtime paths to instantiate classes with untrusted constructor arguments. This vulnerability is fixed in 0.3.85 and 1.3.3.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | langchain-core | >= 1.0.0, <= 1.3.2 | 1.3.3 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Langchain | Langchain | before 0.3.85 from 1.0.0 before 1.3.3 |