{"id":"CVE-2021-48020","title":"Vyper before 0.3.0 Memory Corruption via Internal Function Calls in Arrays","summary":"Vyper from 0.1.0b4 before 0.3.0 contains a memory corruption vulnerability caused by an incorrect stack tip pointer when internal function calls are performed inside arrays. Contracts placing internal calls in nested array elements, exte…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L","cvssSource":"cna","cwe":["CWE-787"],"vendor":"vyperlang","product":"vyper","affected":["vyper >= 0.1.0b4 < 0.3.0"],"published":"2026-10-21","updated":"2026-10-21","sourceUpdated":"2026-10-21T00:36:19.625Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2021-48020","references":[{"url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-22wc-c9wj-6q2v","label":"GitHub Security Advisory (GHSA-22wc-c9wj-6q2v)"},{"url":"https://www.vulncheck.com/advisories/vyper-before-0.3.0-memory-corruption-via-internal-function-calls-in-arrays","label":"VulnCheck Advisory: Vyper before 0.3.0 Memory Corruption via Internal Function Calls in Arrays"}],"tags":["cve.org"],"ingestedAt":"2026-10-21T01:37:08.048Z","slug":"CVE-2021-48020","body":"## Overview\n\nVyper from 0.1.0b4 before 0.3.0 contains a memory corruption vulnerability caused by an incorrect stack tip pointer when internal function calls are performed inside arrays. Contracts placing internal calls in nested array elements, external call arguments, struct literals, or raw_log topics can have memory corrupted, producing incorrect contract behavior.\n\n## Affected\n\n- `vyper >= 0.1.0b4 < 0.3.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}