Pepper — minting limit uses `totalSupply`, blocking legitimate minter airdrops

Source & credit. Reproduction of a public audit finding curated by AuditVault — the original finding: 52222-minting-limit-calculation-may-prevent-legitimate-claims-halb. Standalone Foundry PoC and full write-up: 52222-minting-limit-calculation-may-prevent-legitimate-claims-halb_exp in the evm-hack-registry mirror.

Vulnerability classes: vuln/logic/wrong-condition · vuln/mint/shared-cap · genome: wrong-condition · permanent · reward-accounting

Reproduction: self-contained Foundry PoC with only forge-std. Full trace: output.txt. PoC: test/52222-minting-limit-calculation-may-prevent-legitimate-claims-halb_exp.sol.

AuditVault taxonomy: lang/solidity · platform/halborn · has/poc · severity/high · sector/staking · sector/token · genome: wrong-condition · permanent · reward-accounting

Key info#


Impact	HIGH — once claims (or any non-minter mint path) push `totalSupply` to 40% of max, `MINTER_ROLE` airdrops permanently revert
Protocol	Pepper
Vulnerable code	`mint` — `require(totalSupply() + amount <= MINT_LIMIT)`
Bug class	Shared cap across independent mint paths
Finding	Halborn — Pepper · #52222
Report	halborn.com/audits/pepper/pepper
Source	AuditVault
Status	Audit finding — fixed with separate `minterRoleMintedAmount` tracker. Local synthetic PoC.
Compiler	`^0.8.24` (PoC)

TL;DR#

mint (MINTER_ROLE) caps against global totalSupply, intended as a 40% airdrop budget.
claim also increases totalSupply outside that role.
After claims alone hit MINT_LIMIT, minter airdrops revert even if minters minted 0.
HARM: planned airdrop of 500 tokens is blocked forever (liveness/availability).

The vulnerable code#

SOLIDITY

function mint(address to, uint256 amount) public {
    require(hasRole(MINTER_ROLE, msg.sender), "Must have minter role to mint");
    uint256 _amount = totalSupply() + amount;
    require(_amount <= MINT_LIMIT, "Minting exceeds 40% of total supply"); // @> VULN
    ...
}

Root cause#

The 40% budget was meant for controlled minter mints but is enforced on the sum of all supply sources.

Preconditions#

Claim (or other non-minter) mint path can grow supply toward MINT_LIMIT.
Airdrop still needs to call mint afterward.

Attack walkthrough#

User claims CLAIM_AMOUNT == MINT_LIMIT (40% of max).
Minter calls mint(recipient, 500 ether) → reverts.
HARM: legitimate airdrop permanently blocked.

Diagrams#

flowchart LR Claim["claim path grows totalSupply"] --> Cap["totalSupply == MINT_LIMIT"] Cap --> Block["mint by MINTER_ROLE reverts"] Block --> Harm["airdrop recipients unpaid"]

Impact#

Disrupted token distribution / airdrops; entitled users never receive minter-path tokens.

Sources#

AuditVault finding #52222
Halborn report — Pepper
Remediation hash: bccbd7a5747d4ef6586581ec93ac77e0d8a4de45

Sources & further analysis#

Reproductions & code

Standalone PoC + full trace: 52222-minting-limit-calculation-may-prevent-legitimate-claims-halb_exp (evm-hack-registry mirror).
AuditVault finding: 52222-minting-limit-calculation-may-prevent-legitimate-claims-halb.

Alerts & third-party analyses

Web3Sec X hacked database: search.
Rekt leaderboard: search.
Solodit incident search: search.

These dashboards index community alerts tweets, post-mortems, and independent write-ups. Reach them through the protocol name above to cross-check this reproduction against other analyses.

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