Lending against adequate collateral is one of the main ways in which major central banks can provide liquidity. If such lending is conducted on the basis of a carefully designed collateral management framework (with eligibility criteria and risk control measures being of particular importance), central banks can continue to inject considerable amounts of liquidity into the system without necessarily exposing themselves to additional risk.
This is because, in entering into a repurchase agreement with a counterparty, the central bank is exposed to counterparty risk, but does not itself take on default risk. It can therefore unilaterally select the collateral it accepts, imposing haircuts on that collateral which its counterparties are expected to accept.