CVE-2021-48019

Vyper before 0.2.9 Incorrect RETURNDATASIZE in create_forwarder_to Proxies

MEDIUM
4.8
CVSS Score
Published: October 21, 2026 at 12:36 AM UTC
Updated: October 27, 2026 at 10:17 PM UTC
1 product affected across 1 vendorVyper

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Severity
MEDIUM4.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions
Vendor states this is fixed in 0.2.9 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.8MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-805

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