
Flipcash is a new platform for creating digital currencies. There are many things that make Flipcash unique, but one of the key differences is that every currency has guaranteed USD liquidity from day one. This guaranteed liquidity is managed by the Reserve Contract.
| Target | Type | Severity |
|---|---|---|
https://github.com/code-payments/flipcash-program Copy | Smart Contract | Critical |
https://explorer.solana.com/address/9oREdQzzrVH9HPTqKtVMbwP7fFtjrxVAYkMM664CwMGS Copy | Smart Contract | Critical |
We are interested in the following vulnerabilities:
Vulnerabilities found in out of scope resources are unlikely to be rewarded unless they present a serious business risk (at our sole discretion). In general, the following vulnerabilities do not correspond to the severity threshold:
The list is not limited to the following submissions, but it gives an overview of what issues we care about:
We are looking for evidence and reasons for incorrect behavior of the smart contract, which could cause unintended functionality:
We are happy to thank everyone who submits valid reports which help us improve the security. However, only those that meet the following eligibility requirements may receive a monetary reward:
Flipcash is offering $250,000 USD to the first researcher who can steal BigBeautifulBounty, a test currency created in Flipcash, from our autonomous on-chain Solana smart contract called the Reserve. Context and challenge details are provided below.
Every Flipcash currency is governed by the Reserve contract, an on-chain contract that autonomously manages each currency’s supply and liquidity.
When a new currency is created, 21 million coins are minted and deposited into the Reserve contract. Each currency has a fixed supply of 21 million coins, so there will never be more.
The Reserve contract then sells coins to users on a predefined pricing curve, accepting payment in USDF, a fully backed 1:1 USD stablecoin managed in partnership with Coinbase. The Reserve contract sells the first coin for $0.01 of USDF. It then raises the price slightly and sells the next coin. The predefined pricing curve is gradual but exponential, with the price increasing by approximately one penny per coin for every $11,400 of coins purchased, until the final 21 millionth coin sells for $1 million.
The Reserve contract autonomously self-custodies the USDF it receives. It uses that USDF to also buy coins from users on the same pricing curve. In doing so, the Reserve contract acts as a guaranteed buyer and seller, ensuring continuous liquidity without relying on market makers, order books, or liquidity providers, all in a fully autonomous manner.
When users sell their coins to the Reserve contract, the Reserve contract sets aside 1% of the resulting USDF as a sell fee, paying the remaining 99% to the user. This discourages sandwich attacks.
As sell fees accumulate in the Reserve contract they can be burned at any time without authority, ensuring that these fees can always be burned. These burns are credited to Flipcash as a redemption, which becomes revenue for the protocol.
Over time, the Reserve contract could self-custody billions of dollars of value. Because the Reserve contract is autonomous and will ultimately be immutable, any vulnerability could have severe consequences for the integrity of the Reserves. We have worked hard to ensure the security of the contract, but we want to do everything we can. This is where we could use your help.
We have created a test currency, called BigBeautifulBounty (BBB). You can find it live on-chain here. BBB is managed by our Reserve contract. If you are the first to do one of the following to BBB we will pay you $250,000 USD, subject to eligibility requirements below.
Drain USDF from the Reserve contract, such that holders of BBB can no longer sell their coins to the Reserve contract for at least the expected amount of USDF (allowing for rounding tolerance of $0.01 USDF)
Drain the non-circulating supply of BBB from the Reserve contract, such that users can no longer buy more BBB for a cost of no more than the expected amount of USDF (allowing for rounding tolerance of $0.01 USDF)
Permanently stall the Reserve contract, such that there is no way for holders of BBB to either sell their BBB to the Reserve contract, or buy more BBB from the Reserve contract
The payout will only go to the first person to exploit BBB in one of these three ways, and be able to prove that they were the ones who exploited it first. Final validation and payout eligibility will be determined by Flipcash.
The first valid submission based on the transaction timestamp will get the reward.
To qualify you must steal BBB before March 31, 2026 (23:59 UTC)
We are offering an additional $50,000 USD to anyone who refers a researcher that submits a valid, payout-eligible finding. (The researcher must credit you in their submission).
To support responsible disclosure, we will not pursue legal action against researchers who follow this policy and act in good faith.
Payment for a successful submission will be made in USDC. To remit payment, we must collect basic personal information.
As a US-based company, we cannot pay bounties to individuals residing in countries subject to U.S. trade restrictions or export sanctions, as determined by the Office of Foreign Assets Control (OFAC).
Flipcash reserves the right to update or modify the terms of this bounty. Changes will apply prospectively and will be reflected by the “Last Updated” date above.