abi.encode() with Nested Array

Overview

• Severity: High
• Confidence: High
• Affected Versions: 0.4.7 - 0.5.9

What is the ABI Encoder Array vulnerability?

In certain earlier versions of Solidity, the encoding of nested storage arrays was performed improperly in ways that could lead to smart contract errors. In general, older versions of the Solidity compiler should be avoided by developers, especially those with known bugs such as the improper encoding of storage arrays.

Further reading: Ethereum Foundation Blog: Solidity Storage Array Bug Announcement