Vulnerability in Vyperlang Vyper
CVE-2021-48019
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 .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/vyperlang/vyper/security/advisories/GHSA-375m-5fvv-xq23 (vendor-advisory)
- www.vulncheck.com/advisories/vyper-before-0.2.9-incorrect-returndatasize-in-cre… (third-party-advisory)
Frequently asked questions
- What is CVE-2021-48019?
- CVE-2021-48019 is a medium-severity vulnerability in Vyperlang Vyper, classified under Buffer Access with Incorrect Length Value. CVSS score: 4.8/10. Published 2026-10-21.
- How severe is CVE-2021-48019?
- Medium severity. CVSS v3 base score is 4.8 out of 10.