Flow

Summary

One of the invariant of the protocol can be broken

Vulnerability Details

One of the main protocol invariant is that whenever the RPS equals 0 for a non-voided stream, the stream must be paused, and the Flow.Status should be either PAUSED_SOLVENT or PAUSED_INSOLVENT

This can be observed from the protocol's deocumentation

1. for any non-voided stream, if rps=0⟹isPaused=true and Flow.Status is either PAUSED_SOLVENT or PAUSED_INSOLVENT.

However, this invariant can be easily broken by setting ratePerSecond to zero without pausing the contract. This can be done by calling the adjustRatePerSecond function with newRatePerSecond set to zero. There is no check to ensure that the value is non-zero, which is crucial to maintaining the invariant.

This would mean the invariant has been broken

Impact

Main invariant of the protocol is broken

Tools Used

Manual review

Recommendations

Ensure that whenever the adjustRatePerSecond function is called, the newRatePerSecond is checked to confirm it is non-zero. If newRatePerSecond is zero, the function should revert or automatically pause the contract. This safeguard will enforce the protocol invariant that ratePerSecond must be greater than zero in an active stream, helping to prevent unintended states.