CVE-2023-39363

Advisory

Vyper 0.3.1 includes a fix for an Improper Synchronization vulnerability. In vulnerable versions, 0.2.15, 0.2.16, and 0.3.0, named re-entrance locks are allocated incorrectly. Each function using a named re-entrance lock gets a unique lock regardless of the key, allowing cross-function re-entrance in contracts compiled with the susceptible versions.
https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38

Affected package

Affected versions

Fixed versions

Vulnerability changelog

Vyer 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. Each function using a named re-entrancy lock gets a unique lock regardless of the key, allowing cross-function re-entrancy in contracts compiled with the susceptible versions. A specific set of conditions is required to result in misbehavior of affected contracts, specifically: a `.vy` contract compiled with `vyper` versions `0.2.15`, `0.2.16`, or `0.3.0`; a primary function that utilizes the `@nonreentrant` decorator with a specific `key` and does not strictly follow the check-effects-interaction pattern (i.e. contains an external call to an untrusted party before storage updates); and a secondary function that utilizes the same `key` and would be affected by the improper state caused by the primary function. Version 0.3.1 contains a fix for this issue. See CVE-2023-39363.


MISC:https://github.com/vyperlang/vyper/pull/2439: https://github.com/vyperlang/vyper/pull/2439
MISC:https://github.com/vyperlang/vyper/pull/2514: https://github.com/vyperlang/vyper/pull/2514
MISC:https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38: https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38
MISC:https://hackmd.io/@LlamaRisk/BJzSKHNjn: https://hackmd.io/@LlamaRisk/BJzSKHNjn
MISC:https://hackmd.io/@vyperlang/HJUgNMhs2: https://hackmd.io/@vyperlang/HJUgNMhs2

Resources

• https://github.com/vyperlang/vyper/pull/2439
• https://github.com/vyperlang/vyper/pull/2514
• https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38
• https://hackmd.io/@LlamaRisk/BJzSKHNjn
• https://hackmd.io/@vyperlang/HJUgNMhs2
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-39363