CVE-2023-39363 : Security Advisory and Response

Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM). In versions 0.2.15, 0.2.16, and 0.3.0, named re-entrancy locks are allocated incorrectly, leading to a vulnerability. This article provides insights into CVE-2023-39363.

Understanding CVE-2023-39363

This section delves into the details of the vulnerability identified as CVE-2023-39363 in the Vyper smart contract language.

What is CVE-2023-39363?

Vyper versions 0.2.15, 0.2.16, and 0.3.0 suffer from a vulnerability where named re-entrancy locks are inaccurately allocated, enabling cross-function re-entrancy in contracts compiled with these versions.

The Impact of CVE-2023-39363

Due to incorrect allocation of named re-entrancy locks, affected contracts face misbehavior under specific conditions. This vulnerability poses a medium severity threat with a CVSS base score of 5.9.

Technical Details of CVE-2023-39363

Explore the technical aspects of the CVE-2023-39363 vulnerability in Vyper.

Vulnerability Description

A unique lock is assigned to each function using a named re-entrancy lock, allowing undesirable cross-function re-entrancy. The vulnerability requires a specific set of conditions to manifest.

Affected Systems and Versions

Vyper versions = 0.2.15, = 0.2.16, and = 0.3.0 are impacted by this vulnerability. Users running these versions are advised to take immediate action.

Exploitation Mechanism

The vulnerability arises from the improper allocation of re-entrancy locks, permitting unauthorized re-entry into functions within contracts compiled with the affected Vyper versions.

Mitigation and Prevention

Learn how to mitigate the risks associated with CVE-2023-39363 in Vyper.

Immediate Steps to Take

Users should upgrade to Vyper version 0.3.1, which contains a fix for the incorrectly allocated named re-entrancy locks vulnerability.

Long-Term Security Practices

Developers and users are recommended to adhere to secure coding practices, implement security audits, and stay informed about the latest security updates.

Patching and Updates

Regularly update Vyper to the latest version, follow secure coding guidelines, and monitor official sources for patches and advisories to maintain a secure development environment.