{"cve":"CVE-2023-31146","nvd":{"published":"2023-05-11T21:15:10.240","modified":"2026-06-17T05:56:22.800","status":"Modified","description":"Vyper is a Pythonic smart contract language for the Ethereum virtual machine. Prior to version 0.3.8, during codegen, the length word of a dynarray is written before the data, which can result in out-of-bounds array access in the case where the dynarray is on both the lhs and rhs of an assignment. The issue can cause data corruption across call frames. The expected behavior is to revert due to out-of-bounds array access. Version 0.3.8 contains a patch for this issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","score":9.1},"cwes":["CWE-787"],"references":["https://github.com/vyperlang/vyper/commit/4f8289a81206f767df1900ac48f485d90fc87edb","https://github.com/vyperlang/vyper/security/advisories/GHSA-3p37-3636-q8wv","https://github.com/vyperlang/vyper/commit/4f8289a81206f767df1900ac48f485d90fc87edb","https://github.com/vyperlang/vyper/security/advisories/GHSA-3p37-3636-q8wv"],"products":["vyperlang:vyper"],"source":"nvd","synced_at":"2026-10-19T21:38:18.424950729+00:00"},"epss":{"cve":"CVE-2023-31146","score":0.01252,"percentile":0.69435,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-3p37-3636-q8wv","url":"https://osv.dev/vulnerability/GHSA-3p37-3636-q8wv","summary":"Vyper vulnerable to OOB DynArray access when array is on both LHS and RHS of an assignment","modified":"2026-09-10T03:49:54.489764847Z","packages":[{"ecosystem":"PyPI","name":"vyper","purl":"pkg:pypi/vyper","ranges":["<0.3.8"],"fixed":["0.3.8"]}]},{"id":"PYSEC-2023-77","url":"https://osv.dev/vulnerability/PYSEC-2023-77","summary":"","modified":"2023-11-08T04:12:30.067927Z","packages":[{"ecosystem":"PyPI","name":"vyper","purl":"pkg:pypi/vyper","ranges":["<0.3.8"],"fixed":["0.3.8"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}