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Plume | Attackathon

50409 sc high validator will lose comission

Submitted on Jul 24th 2025 at 10:46:43 UTC by @shadowHunter for Attackathon | Plume Network

Description

Brief/Intro

It seems that currently the contract does not provide any way for a Validator to claim commission on removed tokens (historical). This will cause a genuine Validator to lose commissions.

On removing a token, the contract correctly calls updateRewardPerTokenForValidator to calculate commission till now but fails to provide a way to claim this.

Vulnerability Details

See Proof of Concept section.

Impact Details

Validator will lose commission.

Recommendation

Instead of using _validateIsToken(token) in requestCommissionClaim, check that token is not part of both historical and current reward tokens before rejecting.

Proof of Concept

Step

Reward token T1 exists.

Step

REWARD_MANAGER_ROLE decides to remove it using removeRewardToken.

Step

This calls updateRewardPerTokenForValidator to ensure commission till now is settled:

for (uint256 i = 0; i < $.validatorIds.length; i++) {
    uint16 validatorId = $.validatorIds[i];

    // Final update to current time to settle all rewards up to this point
    PlumeRewardLogic.updateRewardPerTokenForValidator($, token, validatorId);

    // Create a final checkpoint with a rate of 0 to stop further accrual definitively.
    PlumeRewardLogic.createRewardRateCheckpoint($, token, validatorId, 0);
}

Step

The implementation calculates and accumulates the validator commission:

uint256 commissionDeltaForValidator = (
    grossRewardForValidatorThisSegment * commissionRateForSegment
) / PlumeStakingStorage.REWARD_PRECISION;

if (commissionDeltaForValidator > 0) {
    $.validatorAccruedCommission[validatorId][token] += commissionDeltaForValidator;
}

Step

Validator V1 has accrued commission of X amount on Token T1.

Step

Post removal of T1, V1 wants to claim the commission using requestCommissionClaim which calls _validateIsToken(token):

function requestCommissionClaim(
    uint16 validatorId,
    address token
)
    external
    onlyValidatorAdmin(validatorId)
    nonReentrant
    _validateValidatorExists(validatorId)
    _validateIsToken(token)
{
    ...
}

Step

But _validateIsToken(token) reverts since token T1 is now removed:

modifier _validateIsToken(
    address token
) {
    if (!PlumeStakingStorage.layout().isRewardToken[token]) {
        revert TokenDoesNotExist(token);
    }
    _;
}

This causes the validator to be unable to claim the previously accrued commission.