{"id":"CVE-2020-37289","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-37289","generatedAt":"2026-10-27T23:30:04.717Z","title":"Vyper before 0.3.1 lacks a uint8 type, allowing interface return values declared as uint8, such as ERC20.decimals(), to be stored in uint256 variables without bounds checking.","description":"Vyper before 0.3.1 lacks a uint8 type, allowing interface return values declared as uint8, such as ERC20.decimals(), to be stored in uint256 variables without bounds checking. Malicious contracts can return values greater than 255 to manipulate or bypass contract logic that relies on these values.","published":"2026-10-21T01:17:19.000Z","lastModified":"2026-10-22T17:00:33.000Z","status":"Deferred","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":6.3,"severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-20"],"affected":[],"epss":{"score":0.00261,"percentile":0.17778,"date":"2026-10-26","history":[{"date":"2026-10-21","score":0.00261,"percentile":0.16949}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.26%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-21T01:17:19.000Z","detail":{"score":"6.3","severity":"MEDIUM","publishedAt":"2026-10-21T01:17:18.830Z"},"summary":"New CVE, medium severity (CVSS 6.3)."}],"references":[{"url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-mr6r-mvw4-736g","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/vyper-before-0.3.1-improper-input-validation-of-uint8-interface-return-values","source":"disclosure@vulncheck.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-37289","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}