Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
0

CVE-2023-42443

Disclosure Date: September 18, 2023
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM). In version 0.3.9 and prior, under certain conditions, the memory used by the builtins raw_call, create_from_blueprint and create_copy_of can be corrupted. For raw_call, the argument buffer of the call can be corrupted, leading to incorrect calldata in the sub-context. For create_from_blueprint and create_copy_of, the buffer for the to-be-deployed bytecode can be corrupted, leading to deploying incorrect bytecode.

Each builtin has conditions that must be fulfilled for the corruption to happen. For raw_call, the data argument of the builtin must be msg.data and the value or gas passed to the builtin must be some complex expression that results in writing to the memory. For create_copy_of, the value or salt passed to the builtin must be some complex expression that results in writing to the memory. For create_from_blueprint, either no constructor parameters should be passed to the builtin or raw_args should be set to True, and the value or salt passed to the builtin must be some complex expression that results in writing to the memory.

As of time of publication, no patched version exists. The issue is still being investigated, and there might be other cases where the corruption might happen. When the builtin is being called from an internal function F, the issue is not present provided that the function calling F wrote to memory before calling F. As a workaround, the complex expressions that are being passed as kwargs to the builtin should be cached in memory prior to the call to the builtin.

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CVSS V3 Severity and Metrics
Base Score:
8.1 High
Impact Score:
5.9
Exploitability Score:
2.2
Vector:
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
High
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

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