## Description The `SoulboundProfileNFT::blockProfile` function uses `delete profileToToken[blockAddress]`, which resets `profileToToken[blockAddress]` to `0`. Since the mintProfile function checks for an existing profile by verifying that `profileToToken[msg.sender] == 0`, a blocked account can be recreated by simply minting a new profile. This behavior bypasses the intended permanent block functionality. ## Vulnerability Details By deleting the mapping entry for a blocked account, the contract inadvertently allows a new mintProfile call to pass the check `require(profileToToken[msg.sender] == 0, "Profile already exists")`. Essentially, once an account is blocked, its associated mapping entry is cleared, so the condition to identify an account with an existing profile is no longer met. This loophole enables a blocked account to recreate its profile, undermining the purpose of blocking. ## Impact A blocked account, which should be permanently barred from engaging with the platform, can circumvent this restriction by re-minting its profile. The integrity of the platform is compromised, as blocked users could regain access and potentially perform further malicious actions. ## POC ```solidity function testRecereationOfBlockedAccount() public { // Alice mints a profile successfully vm.prank(user); soulboundNFT.mintProfile("Alice", 18, "ipfs://profileImageAlice"); // Owner blocks Alice's account, which deletes Alice profile mapping vm.prank(owner); soulboundNFT.blockProfile(user); // The blocked user (Alice) attempts to mint a new profile. // Due to the reset mapping value (0), the require check is bypassed. vm.prank(user); soulboundNFT.mintProfile("Alice", 18, "ipfs://profileImageAlice"); } ``` ## Recommendations - When blocking an account, implement a mechanism to permanently mark that address as blocked rather than simply deleting an entry. For example, maintain a separate mapping (e.g., isBlocked) to record blocked accounts, and update mintProfile to check if an account is permanently barred from minting: Example modification: ```diff + mapping(address => bool) public isBlocked; ... function mintProfile(string memory name, uint8 age, string memory profileImage) external { + require(!isBlocked[msg.sender], "Account is permanently blocked"); require(profileToToken[msg.sender] == 0, "Profile already exists"); uint256 tokenId = ++_nextTokenId; _safeMint(msg.sender, tokenId); // Store metadata on-chain _profiles[tokenId] = Profile(name, age, profileImage); profileToToken[msg.sender] = tokenId; emit ProfileMinted(msg.sender, tokenId, name, age, profileImage); } ... function blockProfile(address blockAddress) external onlyOwner { uint256 tokenId = profileToToken[blockAddress]; require(tokenId != 0, "No profile found"); _burn(tokenId); delete profileToToken[blockAddress]; delete _profiles[tokenId]; + isBlocked[blockAddress] = true; emit ProfileBurned(blockAddress, tokenId); } ```