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Advisory record · GHSA-pjwx-r37v-7724

LangChain vulnerable to unsafe deserialization of attacker-controlled objects through overly broad `load()` allowlists

CVSS 8.2 HighEPSS 0.0041 · 35th percentile

Published by the GitHub Advisory Database at 8 May 2026, 23:07 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
langchain-corePyPI>=1.0.0, <1.3.3 || <0.3.851.3.3, 0.3.85
Identifiers
GHSA-pjwx-r37v-7724 · CVE-2026-44843 · PYSEC-2026-2564
Weakness (CWE)
CWE-502
Tags
Published
8 May 2026
Updated
10 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The langchain-core package, versions before 0.3.85 and from 1.0.0 up to 1.3.3, has overly broad object allowlists in some runtime code paths that deserialize run data. An attacker who can submit untrusted structured input that gets preserved in run inputs or outputs, in an application using RunnableWithMessageHistory, astream_log(), or astream_events(version="v1"), may be able to get trusted LangChain classes instantiated with attacker-controlled arguments. Upgrade langchain-core to 0.3.85 or 1.3.3.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
8.2 High 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0041, the 35th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 5 May 2026, 21:00 UTC Published by the maintainers as a GitHub repository advisory
  2. 31 Oct 2026, 14:11 UTC First seen by agentprime
  3. 31 Oct 2026, 14:11 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.