{"api_version":"1","generated_at":"2026-04-23T15:10:14+00:00","cve":"CVE-2023-39363","urls":{"html":"https://cve.report/CVE-2023-39363","api":"https://cve.report/api/cve/CVE-2023-39363.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2023-39363","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-39363"},"summary":{"title":"CVE-2023-39363","description":"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. 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.","state":"PUBLIC","assigner":"security-advisories@github.com","published_at":"2023-08-07 19:15:00","updated_at":"2023-09-18 21:15:00"},"problem_types":["CWE-863"],"metrics":[],"references":[{"url":"https://hackmd.io/@vyperlang/HJUgNMhs2","name":"https://hackmd.io/@vyperlang/HJUgNMhs2","refsource":"MISC","tags":[],"title":"Vyper Nonreentrancy Lock Vulnerability Technical Post-Mortem Report - HackMD","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://hackmd.io/@LlamaRisk/BJzSKHNjn","name":"https://hackmd.io/@LlamaRisk/BJzSKHNjn","refsource":"MISC","tags":[],"title":"Curve Pool Reentrancy Exploit Postmortem July 30th, 2023 - HackMD","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://github.com/vyperlang/vyper/pull/2514","name":"https://github.com/vyperlang/vyper/pull/2514","refsource":"MISC","tags":[],"title":"fix codegen failure with nonreentrant keys by charles-cooper · Pull Request #2514 · vyperlang/vyper · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38","name":"https://github.com/vyperlang/vyper/security/advisories/GHSA-5824-cm3x-3c38","refsource":"MISC","tags":[],"title":"Incorrectly allocated named re-entrancy locks · Advisory · vyperlang/vyper · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/vyperlang/vyper/pull/2439","name":"https://github.com/vyperlang/vyper/pull/2439","refsource":"MISC","tags":[],"title":"Fix unused storage slots by charles-cooper · Pull Request #2439 · vyperlang/vyper · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://www.cve.org/CVERecord?id=CVE-2023-39363","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-39363","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2023","cve_id":"39363","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"vyperlang","cpe5":"vyper","cpe6":"0.2.15","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"python","cpe12":"*","cpe13":"*"},{"cve_year":"2023","cve_id":"39363","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"vyperlang","cpe5":"vyper","cpe6":"0.2.16","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"python","cpe12":"*","cpe13":"*"},{"cve_year":"2023","cve_id":"39363","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"vyperlang","cpe5":"vyper","cpe6":"0.3.0","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"python","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[{"cve":"CVE-2023-39363","qid":"994800","title":"Python (Pip) Security Update for vyper (GHSA-5824-cm3x-3c38)"}]},"source_records":{"cve_program":{"data_version":"4.0","data_type":"CVE","data_format":"MITRE","CVE_data_meta":{"ID":"CVE-2023-39363","ASSIGNER":"security-advisories@github.com","STATE":"PUBLIC"},"description":{"description_data":[{"lang":"eng","value":"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. 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. 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