{"id":"CVE-2021-48019","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-48019","generatedAt":"2026-10-27T21:45:57.541Z","title":"Calls through these proxies can yield corrupted data when a function returns more than 4096 bytes without return data sanitation, and fail strict return-size checks such as SafeERC20.safeTransfer.","description":"Vyper before 0.2.9 deploys forwarder proxies through the built-in create_forwarder_to function that report a fixed 4096-byte RETURNDATASIZE rather than the actual return data size. Calls through these proxies can yield corrupted data when a function returns more than 4096 bytes without return data sanitation, and fail strict return-size checks such as SafeERC20.safeTransfer.","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:L/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-805"],"affected":[],"epss":{"score":0.00248,"percentile":0.15926,"date":"2026-10-26","history":[{"date":"2026-10-21","score":0.00248,"percentile":0.15155}]},"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 (0.25%). 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":"2026-10-21T01:17:19.130Z"},"summary":"New CVE, medium severity (CVSS 6.3)."}],"references":[{"url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-375m-5fvv-xq23","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/vyper-before-0.2.9-incorrect-returndatasize-in-create-forwarder-to-proxies","source":"disclosure@vulncheck.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-48019","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."}