CVE-2023-31146
📋 TL;DR
This vulnerability in Vyper smart contract language allows out-of-bounds array access during dynamic array assignments, potentially causing data corruption across call frames. It affects Ethereum smart contracts written in Vyper versions before 0.3.8. The issue can lead to unexpected contract behavior instead of properly reverting transactions.
💻 Affected Systems
- Vyper smart contract language
📦 What is this software?
Vyper by Vyperlang
⚠️ Risk & Real-World Impact
Worst Case
Smart contract data corruption leading to financial loss, contract malfunction, or unauthorized state changes in DeFi protocols or other Ethereum applications.
Likely Case
Smart contract execution errors causing failed transactions, unexpected behavior, or minor data inconsistencies in affected contracts.
If Mitigated
Proper input validation and contract auditing would limit impact, but the compiler-level bug could still cause issues in edge cases.
🎯 Exploit Status
Exploitation requires specific smart contract code patterns and understanding of Vyper's compilation process.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.3.8
Vendor Advisory: https://github.com/vyperlang/vyper/security/advisories/GHSA-3p37-3636-q8wv
Restart Required: No
Instructions:
Update Vyper compiler to version 0.3.8 or later using pip: pip install vyper==0.3.8
Recompile all existing smart contracts with the updated compiler
Deploy updated contract versions to replace vulnerable contracts
🔧 Temporary Workarounds
Avoid vulnerable code patterns
allAvoid using the same dynamic array on both sides of assignments in smart contract code
🧯 If You Can't Patch
- Audit all smart contracts for dynamic array assignment patterns where same array appears on both sides
- Implement additional runtime checks in smart contracts to validate array bounds before operations
🔍 How to Verify
Check if Vulnerable:
Check Vyper compiler version: vyper --version. If version is less than 0.3.8, you are vulnerable.Check Version:
vyper --versionVerify Fix Applied:
Verify vyper --version returns 0.3.8 or higher. Test compilation of contracts with dynamic array assignments.📡 Detection & Monitoring
Log Indicators:
- Failed contract deployments
- Unexpected contract behavior
- Transaction reverts with array-related errors
Network Indicators:
- Unusual contract interactions involving array operations
- Failed transactions on contracts using dynamic arrays
SIEM Query:
Not applicable - this is a compiler-level issue affecting smart contract execution🔗 References
- https://github.com/vyperlang/vyper/commit/4f8289a81206f767df1900ac48f485d90fc87edb
- https://github.com/vyperlang/vyper/security/advisories/GHSA-3p37-3636-q8wv
- https://github.com/vyperlang/vyper/commit/4f8289a81206f767df1900ac48f485d90fc87edb
- https://github.com/vyperlang/vyper/security/advisories/GHSA-3p37-3636-q8wv
