{"id":"PYSEC-2023-142","details":"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.","aliases":["CVE-2023-39363","GHSA-5824-cm3x-3c38"],"modified":"2025-10-09T08:26:23.283831Z","published":"2023-08-07T19:15:00Z","references":[{"type":"ADVISORY","url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38"},{"type":"WEB","url":"https://hackmd.io/@LlamaRisk/BJzSKHNjn"},{"type":"WEB","url":"https://hackmd.io/@vyperlang/HJUgNMhs2"},{"type":"FIX","url":"https://github.com/vyperlang/vyper/pull/2514"},{"type":"FIX","url":"https://github.com/vyperlang/vyper/pull/2439"}],"affected":[{"package":{"name":"vyper","ecosystem":"PyPI","purl":"pkg:pypi/vyper"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.1.0b1","0.1.0b10","0.1.0b11","0.1.0b12","0.1.0b13","0.1.0b14","0.1.0b15","0.1.0b16","0.1.0b17","0.1.0b2","0.1.0b3","0.1.0b4","0.1.0b5","0.1.0b6","0.1.0b7","0.1.0b8","0.1.0b9","0.2.1","0.2.10","0.2.11","0.2.12","0.2.13","0.2.14","0.2.15","0.2.16","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.2.7","0.2.8","0.2.9","0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9","0.3.10","0.3.10rc1","0.3.10rc2","0.3.10rc3","0.3.10rc4","0.3.10rc5","0.4.0","0.4.0b1","0.4.0b2","0.4.0b3","0.4.0b4","0.4.0b5","0.4.0b6","0.4.0rc1","0.4.0rc2","0.4.0rc3","0.4.0rc4","0.4.0rc5","0.4.0rc6","0.4.1","0.4.1b1","0.4.1b2","0.4.1b3","0.4.1b4","0.4.1rc1","0.4.1rc2","0.4.1rc3","0.4.2","0.4.2rc1","0.4.3","0.4.3rc1"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/vyper/PYSEC-2023-142.yaml"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}