VIP-663: [BNB Chain Testnet] Set vBNB Collateral Factor to 0

[Debugger022]

Description
This proposal sets the Collateral Factor (CF) of the vBNB market in the Core Pool on BNB Chain Testnet to 0, while keeping the Liquidation Threshold (LT) unchanged at 80%.
Setting CF to 0 disables the ability to open new borrows backed by BNB as collateral. Keeping LT at its current value ensures existing borrowers using BNB as collateral remain in their current health state and are not forced into liquidation by this change.

Changes

• Update vBNB risk parameters on the Core Pool Unitroller via setCollateralFactor(address,uint256,uint256)
  • vBNB Collateral Factor — Current: 80% → Proposed: 0%
  • vBNB Liquidation Threshold — Current: 80% → Proposed: 80% (unchanged)

Contracts

Contract	Address
Unitroller (Core Pool Comptroller)	0x94d1820b2D1c7c7452A163983Dc888CEC546b77D
vBNB	0x2E7222e51c0f6e98610A1543Aa3836E092CDe62c

Summary

If approved, this VIP will:

• Set the vBNB Collateral Factor to 0, preventing new borrows from being opened against BNB as collateral
• Preserve the vBNB Liquidation Threshold at 80%, keeping existing borrower positions in their current health state.

Test plan

• npx hardhat test simulations/vip-663/bsctestnet.ts --fork bsctestnet
• Pre-VIP: CF = 0.80, LT = 0.80 (verified on-chain at block
  100039209)
• Post-VIP: CF = 0, LT = 0.80 (unchanged)

[Debugger022]

https://venus-testnet.vercel.app/#/governance/proposal/664?chainId=97