Deserialization in Langchain
CVE-2026-44843
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.
Vulnerability class: Insecure Deserialization
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (29.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: -0.000
Affected products
- Langchain
- Langchain-Ai Langchain — versions < 0.3.85, >= 1.0.0a1, < 1.3.3
Weakness classification (CWE)
References
- github.com/langchain-ai/langchain/security/advisories/GHSA-pjwx-r37v-7724 (Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-44843?
- CVE-2026-44843 is a high-severity vulnerability in Langchain, classified under Deserialization of Untrusted Data. CVSS score: 8.2/10. Published 2026-05-26.
- How severe is CVE-2026-44843?
- High severity. CVSS v3 base score is 8.2 out of 10.