CVE-2026-48775: langgraph-checkpoint - Unsafe JSON Deserialization in Checkpoint Loading
Summary
CVE-2026-48775: LangGraph Checkpoint: Unsafe JSON deserialization in checkpoint loading. Affects langgraph-checkpoint versions < 4.1.1. Fixed in 4.1.1. How to fix ↓
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Background
LangGraph is a framework designed for building and managing machine learning models, providing functionalities such as checkpointing for model states. The package includes a default serializer, JsonPlusSerializer, which reconstructs Python objects from JSON checkpoint payloads. This functionality is essential for resuming model training or inference from saved states. However, it also introduces security risks if the checkpoint data can be tampered with.
Vulnerability Detail
The vulnerability arises from LangGraph's JsonPlusSerializer, which allows for the reconstruction of Python objects from JSON checkpoint payloads. If an unauthorized party can modify the checkpoint bytes in the backing store, they could exploit this deserialization process to reconstruct unexpected objects, potentially leading to arbitrary code execution during checkpoint loading. This issue is particularly concerning in environments where checkpoint stores are not adequately secured, as it escalates the risk from mere write access to the checkpoint store to full code execution within the LangGraph worker process.
How To Fix
Latest published version: 4.3.0 as of 23 Oct 2026
pip install --upgrade "langgraph-checkpoint==4.3.0"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
4.1.1
This is the first release that contains the fix.
pip install --upgrade "langgraph-checkpoint==4.1.1"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, treat checkpoint stores as integrity-sensitive. Restrict write access and rotate credentials if unauthorized access is suspected. Avoid using custom JSON revival hooks that reconstruct arbitrary types unless the checkpoint data is fully trusted.
Conclusion
The CVE-2026-48775 vulnerability in the langgraph-checkpoint package poses a significant risk due to unsafe JSON deserialization. Users are advised to update to version 4.1.1 or later to mitigate this risk. Additionally, employing best practices for securing checkpoint stores can further protect against potential exploits.
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FAQ
CVE-2026-48775 is a vulnerability in the langgraph-checkpoint package that allows for unsafe JSON deserialization, potentially leading to arbitrary code execution.
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The primary risk is arbitrary code execution during checkpoint deserialization, which could expose runtime secrets or allow unauthorized access to other systems.
If an immediate update is not possible, ensure that your checkpoint store is secure and restrict write access to prevent unauthorized modifications.
There is currently no evidence of this vulnerability being exploited in the wild, but it is important to address it to reduce potential risks.
References
Related vulnerabilities
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