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In yesterday’s Alpha Dispatch, I lauded Marinade Finance’s impressive week, which included the beta launch of Instant Unstake and some promising governance improvements.
I may have spoken prematurely.
Less than 24 hours later, the Shiroi project published an incident report alleging that malicious validators have been exploiting Marinade’s Stake Auction Marketplace (SAM) for over a year.
According to Shiroi’s independent audit, at least 37,000 SOL in rewards — worth more than $6.5 million at the time of publication — were siphoned away from the protocol over 126 epochs, allegedly leaving stakers short-changed.
Marinade’s auction-based delegation system is at the core of the issue. The way it’s supposed to work is that validators bid for stake, and the protocol distributes delegation accordingly. However, according to Shiroi, the system has allowed select validators to receive stake without paying for it; supposedly as much as 75% of the delegated amount in a single epoch.
Across the data set, Shiroi alleges that the unpaid share averaged 28%, potentially nullifying a significant portion of Marinade’s advertised APY for stakers.
The report names names, publishing a list of the Top 10 most exploitative validators, many of which are still active on Marinade, and some of whom appear to be backed by Jito or the Solana Foundation. The team says it also identified 24 epochs where over 50% of the delegated stake went unpaid.
Shiroi claims that multiple attempts to contact Marinade’s core team went unanswered.
To be fair, Marinade had publicly addressed related concerns (as it often does) just a few days before Shiroi’s report, though its focus was specifically on sandwich attacks — another exploitative behavior tied to the auction system.
In a May 5 post, the team called sandwiching a “cat and mouse game.” It noted its continuous blacklisting of malicious validators, and pledged to integrate external detection data and launch a set of KYB-verified ethical validators. While not a direct response to Shiroi’s findings, it acknowledged systemic risks within SAM that many believe have enabled both types of abuse.
Critics remain unsatisfied for now. Some, like Spectrum Staking, pointed to the Shiroi report as validation of longstanding concerns, saying “it is sad to see [this] once-great pioneer of staking pools in such a state.” Others, like Hanabi Staking, requested a more proactive investigation of validator behavior, correlating auction abuse with validator bonding configurations and historical patterns.
Shiroi has promised to provide its full “methodology, calculations and proofs” in the coming days.
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