{"id":"CVE-2021-48019","aliases":[],"title":"Vyper before 0.2.9 Incorrect RETURNDATASIZE in create_forwarder_to Proxies","titleSource":"VulnCheck","descriptionSource":"VulnCheck","products":[{"vendor":"vyperlang","name":"vyper","platforms":[],"versions":[{"version":"0","status":"affected","lessThan":"0.2.9","versionType":"python"},{"version":"0.2.9","status":"unaffected","versionType":"python"}],"defaultStatus":"unaffected","source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2021-48019"}],"remediation":[],"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.","severity":"medium","score":6.3,"published":"2026-10-21T00:36:18.960Z","modified":"2026-10-27T21:35:59.282Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://github.com/vyperlang/vyper/security/advisories/GHSA-375m-5fvv-xq23","https://www.vulncheck.com/advisories/vyper-before-0.2.9-incorrect-returndatasize-in-create-forwarder-to-proxies"],"sources":[{"name":"CVE","id":"CVE-2021-48019","modified":"2026-10-27T21:35:59.282Z","url":"https://www.cve.org/CVERecord?id=CVE-2021-48019"}],"assessments":[{"source":"VulnCheck","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","score":6.3},{"source":"VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","score":4.8}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T20:45:31.448Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}