🏑Missing Duplicate Veto Check

In governance systems, vetoing a proposal is a critical feature that allows designated parties, often members of a council, to stop a proposal from moving forward if it is deemed harmful or inappropriate. However, if the veto mechanism is not properly designed, it can be exploited by allowing duplicate vetoes on the same proposal. This creates potential for multiple veto actions, which can cause issues such as unintended behavior in the governance flow or disruption in the proposal lifecycle.

In this section, we will explore the vulnerability of missing duplicate veto checks and its potential impact, as well as how to mitigate it effectively.

Vulnerability Details

In the provided GovernorAlpha contract, the veto function allows council members to veto a proposal if they believe it should not be executed. However, the contract does not include a check to prevent duplicate vetoes. This means that a single proposal can be vetoed multiple times, even after it has already been vetoed, leading to unnecessary and potentially disruptive actions in the governance process.

Impact

1. Redundant or Confusing Actions: Allowing multiple vetoes on a single proposal can create unnecessary complexity or confusion within the governance system. Each duplicate veto may trigger redundant actions such as logging multiple veto events or attempting to queue or cancel the proposal multiple times, disrupting the governance flow.

2. Disruption of Governance Logic: Duplicate veto actions could interfere with the proper functioning of the governance system, causing unexpected behavior such as invalidating a valid proposal, triggering contradictory outcomes, or leading to excessive gas usage for no reason.

3. Trust and Integrity Issues: Governance participants may lose trust in the system if they observe that proposals can be vetoed multiple times, leading to a perception of instability or manipulation in the governance process.