Bug 2565617

Summary: CVE-2021-48019 vyper: vyper: data corruption via fixed return data size in forwarder proxies [fedora-all]
Product: [Fedora] Fedora Reporter: TEJ RATHI <trathi>
Component: vyperAssignee: Peter Lemenkov <lemenkov>
Status: CLOSED CURRENTRELEASE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: lemenkov
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["5054bbc2-c76e-41c5-a1b9-e2cd2e43eb50"]}
Fixed In Version: vyper-0.2.9 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-11-03 07:42:54 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2558000    

Description TEJ RATHI 2026-11-03 07:39:24 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.
Comment 1 Peter Lemenkov 2026-11-03 07:42:54 UTC 
This was fixed upstream in vyper 0.2.9 (GHSA-375m-5fvv-xq23 / VVE-2021-0002, published 2021-04-16).

All Fedora releases ship vyper 0.4.3, which already contains the fix and is not affected.