{"id":"CVE-2021-48019","published":"2026-10-21T01:17:19.130","lastModified":"2026-10-22T17:00:33.203","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.","cvssScore":4.8,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","cwes":["CWE-805"],"vendors":[],"products":[],"references":[{"url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-375m-5fvv-xq23","tags":[]},{"url":"https://www.vulncheck.com/advisories/vyper-before-0.2.9-incorrect-returndatasize-in-create-forwarder-to-proxies","tags":[]}],"exploitRefs":[{"url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-375m-5fvv-xq23","tags":[]}],"hasPoc":true,"ai":null}