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Floating Pragma

This page explains the floating pragma vulnerability in smart contracts.

Description​

A floating pragma in a smart contract allows the contract to be compiled with any version of the compiler that meets the specified version range. For example, a pragma like pragma solidity ^0.8.0; indicates compatibility with any version from 0.8.0 up to, but not including, 0.9.0. While this can provide flexibility, it may also introduce compatibility issues with future versions of the compiler.

Impact on Smart Contracts​

Using a floating pragma can lead to unexpected behavior if a newer compiler introduces breaking changes or modifies existing functionalities. This can result in contract malfunctions, loss of funds, or unexpected vulnerabilities that were not present during the initial deployment.

Lua Code Example​

-- Lua example demonstrating a floating pragma vulnerability
-- Assume this is part of a larger Lua script that specifies compatibility with a range of Lua versions
function checkCompatibility(version)
    if version >= 5.1 and version < 5.4 then
        print("Compatible version")
    else
        print("Incompatible version")
    end
end

-- Example usage
checkCompatibility(5.3)  -- Output: Compatible version
checkCompatibility(5.4)  -- Output: Incompatible version
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