LangChain: Unsafe deserialization of attacker-controlled LangChain objects through overly broad `load()` allowlists

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Summary

CVECVE-2026-44843
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-26 21:16:39 UTC
Updated2026-05-29 19:48:48 UTC
DescriptionLangChain 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.

Risk And Classification

Primary CVSS: v3.1 8.2 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

EPSS: 0.000450000 probability, percentile 0.141500000 (date 2026-06-02)

Problem Types: CWE-502 | CWE-502 CWE-502: Deserialization of Untrusted Data

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
3.1CNADECLARED8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Langchain Langchain All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Langchain-ai Langchain affected < 0.3.85 Not specified
CNA Langchain-ai Langchain affected >= 1.0.0a1, < 1.3.3 Not specified

References

ReferenceSourceLinkTags
github.com/langchain-ai/langchain/security/advisories/GHSA-pjwx-r37v-7724 [email protected] github.com Mitigation, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
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