# Whale can DoS Uniswap pools

Colorpool's UniswapV2 clone burns MINIMUM_LIQUIDITY instead of locking it, letting a whale mint 1 LP share, donate reserves, and DoS other LPs and swaps.

- Payout: Contest reward
- Severity: medium
- Program: Super Sushi Samurai
- Credited: 0xb0k0
- Disclosed: 2025-05-15
- Write-up quality: 6/10
- Original: https://cdn.cantina.xyz/reports/cantina_competition_super_sushi_samurai_march2025.pdf#3.2.3
- Library page: https://bugbountylibrary.com/r/cantina%3Asuper_sushi_samurai_march2025%3A3.2.3
- Tags: domain:web3 impact:dos kind:contest platform:cantina sev:medium tech:solidity technique:regression technique:source-review vuln:business-logic vuln:dos vuln:share-inflation

**Target:** Colorpool DEX UniswapV2 clone add_liquidity/mint
**Root cause:** On first mint, MINIMUM_LIQUIDITY is minted then burned, reducing total supply back to the user's liquidity instead of permanently locking it at address 0.
**Steps:**
1. Deploy USDC/BTC tokens and create pair
2. Whale calls `add_liquidity` with minimal amounts (1001/1001) to mint exactly 1 LP share
3. Whale transfers large amounts of both tokens directly to `pair.treasury` and calls `sync`
4. Victim `add_liquidity` reverts with `UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED` because minted liquidity rounds to 0
5. Whale `remove_liquidity` of 1 share; subsequent swaps revert with `UniswapV2Library: INSUFFICIENT_LIQUIDITY`
**How found:** Code review of the mint function against UniswapV2 reference: noticed MINIMUM_LIQUIDITY is burned rather than locked, so total supply does not retain the locked share.
**Exploitation:** Whale seeds the pool with 1 wei-scale LP, donates huge token balances to the treasury so any new LP's share computes to 0, blocking liquidity provision; removing the 1 share leaves reserves at 0 and breaks swaps.
**Insight:** When auditing UniswapV2 forks, diff the first-mint branch against upstream: any deviation in how MINIMUM_LIQUIDITY is handled (burn vs lock, or minted to caller) reopens the classic first-depositor inflation/DoS vector.