CVE-2025-56207
📋 TL;DR
A vulnerability in the Money Making Opportunity (MMO) ERC721 NFT smart contract allows users to transfer NFTs to the zero address (0x0), resulting in permanent loss of those assets. This violates the ERC721 standard requirement that prevents transfers to zero addresses. NFT holders and the contract owner are affected by this flaw.
💻 Affected Systems
- MoneyMakingOpportunity smart contract
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
All NFTs in the contract could be permanently lost if transferred to the zero address, rendering the entire collection worthless and causing significant financial loss to all holders.
Likely Case
Accidental or malicious transfers of individual NFTs to the zero address, resulting in permanent loss of those specific assets for their owners.
If Mitigated
If proper validation is implemented, all transfers to zero addresses would be rejected, preventing any asset loss.
🎯 Exploit Status
Exploitation requires calling the vulnerable _transfer function with the zero address as recipient. This could be done through the contract's public transfer functions or direct contract interaction.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not versioned - requires contract redeployment
Vendor Advisory: https://github.com/Monekon/CVE/blob/main/Vulnerabilities/MMO_Transfer_to_ZeroAddress.md
Restart Required: No
Instructions:
1. Create a new version of the MoneyMakingOpportunity contract with proper zero address validation in the _transfer function. 2. Deploy the new contract to the Ethereum network. 3. Migrate all NFTs from the old contract to the new contract address. 4. Update all integrations and frontends to use the new contract address.
🔧 Temporary Workarounds
Implement transfer validation wrapper
EthereumCreate a wrapper contract that intercepts all transfer calls and validates recipients are not zero addresses before forwarding to the vulnerable contract.
🧯 If You Can't Patch
- Educate all users to never attempt transfers to the zero address and verify recipient addresses carefully.
- Implement monitoring to detect and alert on any transfers to the zero address from the vulnerable contract.
🔍 How to Verify
Check if Vulnerable:
Review the contract source code at address 0x41d3d86a84c8507a7bc14f2491ec4d188fa944e7 and check if the _transfer function validates that the recipient address is not 0x0.Check Version:
Not applicable - smart contracts don't have traditional version commands. Check the contract bytecode hash or deployment transaction.Verify Fix Applied:
Deploy the patched contract and test that transfer attempts to the zero address (0x0) are rejected with a revert.📡 Detection & Monitoring
Log Indicators:
- Ethereum transaction logs showing Transfer events with 'to' address set to 0x0000000000000000000000000000000000000000
Network Indicators:
- Transactions calling the transfer or safeTransferFrom functions with zero address as parameter
SIEM Query:
Not applicable - blockchain transactions are public and immutable, not logged in traditional SIEM systems.