#46218 [SC-Insight] Documentation-Implementation Discrepancy in Agent Vault Access Control

Submitted on May 26th 2025 at 20:30:49 UTC by @Victor_TheOracle for Audit Comp | Flare | FAssets

• Report ID: #46218

• Report Type: Smart Contract

• Report severity: Insight

• Target: https://github.com/flare-foundation/fassets/blob/main/contracts/assetManager/implementation/AgentVault.sol

• Impacts:

Description

Brief/Intro

The depositCollateral and updateCollateral functions in the Agent Vault contract are documented to be callable by anyone but are implemented with onlyOwner modifiers, restricting access to vault owners only. This prevents third-party funding mechanisms and flexible collateral management as described in the documentation.

Vulnerability Details

The documentation explicitly states that both depositCollateral and updateCollateral should be callable by anybody:

Documentation Claims:

• depositCollateral: "NOTE: anybody can call this method, to allow the owner to deposit from any wallet."

• updateCollateral: "NOTE: anybody can call this method, to allow the owner to deposit from any source."

Actual Implementation:

function depositCollateral(IERC20 _token, uint256 _amount)
    external override
    onlyOwner  //@audit Contradicts documentation
{
    _token.safeTransferFrom(msg.sender, address(this), _amount);
    assetManager.updateCollateral(address(this), _token);
    _tokenUsed(_token, TOKEN_DEPOSIT);
}

function updateCollateral(IERC20 _token)
    external override
    onlyOwner  //@audit Contradicts documentation
{
    assetManager.updateCollateral(address(this), _token);
    _tokenUsed(_token, TOKEN_DEPOSIT);
}

This implementation shows that it has deviated from what was documented.

Impact Details

The primary consequence of this access control discrepancy is loss of flexibility as third parties cannot assist with collateral management despite this functionality being explicitly documented.

References

1. AgentVault documentation for the depositCollateral, and updateCollateral functions: https://github.com/flare-foundation/fassets/blob/fc727ee70a6d36a3d8dec81892d76d01bb22e7f1/docs/IAgentVault.md?plain=1#L1-L5

2. AgentVault implementation: https://github.com/flare-foundation/fassets/blob/fc727ee70a6d36a3d8dec81892d76d01bb22e7f1/contracts/assetManager/implementation/AgentVault.sol#L93-L109

Proof of Concept

1. The documentation clearly states that anybody can call the depositCollateral and updateCollateral methods, to allow the owner to deposit from any wallet or source.

https://github.com/flare-foundation/fassets/blob/fc727ee70a6d36a3d8dec81892d76d01bb22e7f1/docs/IAgentVault.md?plain=1#L1-L5

**depositCollateral** - Deposit vault collateral. Parameter `_token` is explicit to allow depositing before collateral switch.
NOTE: owner must call `token.approve(vault, amount)` before calling this method. NOTE: anybody can call this method, to allow the owner to deposit from any wallet.

**updateCollateral** - Update collateral after `transfer(vault, some amount)` was called (alternative to depositCollateral). Parameter `_token` is explicit to allow depositing before collateral switch.
NOTE: anybody can call this method, to allow the owner to deposit from any source.

1. Owner tries to deposit or update collateral from another wallet, but the transaction fails with the "Ownable: caller is not the owner" error.

2. This does not align with the documentation and it should be corrected.