LangChain: LangChain vulnerable to unsafe deserialization of attacker-controlled objects through overly…
LangChain
More for LangChain RSS feed for LangChain
- Severity
- High, CVSS 8.2
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
- Record
- CVE-2026-44843
- Affects
- LangChain
- Known exploited
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Published
- Record first published by the source
- May 26, 2026
- Source last modified
- July 24, 2026
Description
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.
Description quoted from the NVD record.
Who is affected
LangChain is a toolkit software developers use to build apps and AI assistants that use AI language models. This flaw affects versions before 0.3.85 and 1.3.3. Some older parts of the product that read back stored data, such as the inputs and outputs of a run, accept a wider range of LangChain objects than they need. As a result, an attacker who can supply such data could make your app create LangChain objects using settings the attacker chose. It does not let an attacker load any arbitrary program object. This flaw is rated High.
What to do
- Find out whether any app your organization uses was built with LangChain. The developer who built it, or the IT provider or vendor that runs it, can tell you.
- If your own staff or volunteers run the app, have that person update LangChain to version 0.3.85 or 1.3.3, or a later release. These versions fix this flaw.
- If an IT provider or vendor builds or runs the app for you, send them this advisory and ask when the update will be done.
Analysis written from the source record as of July 24, 2026 and reviewed before publishing.