BloomThis NFT smart contract security audit conducted by the Callisto Network Security Department in February 2023.

BloomThis NFT (V2) Security Audit Report

Are Your Funds Safe?


1. In scope

2. Findings

In total, 0 issue were reported, including:

  • 0 high severity issues.

  • 0 medium severity issues.

  • 0 low severity issue.

In total, 6 notes were reported, including:

  • 3 notes.

  • 3 owner privileges.

2.1 Owner privileges

Severity: Owner privileges.


  1. New NFT tokens can only be minted by an authorized admin using the function mint().

  2. Token fusion rules can only be added by an authorized admin using the function addFusionRule().

  3. The royalty fee collected by admins can be changed by the admin using the function setRoyaltyInfo() for the rewards collected impacting the reward per token for the users.

2.2 Infinite minting of tokens possible

Severity: Note.


If _maxTokens is initialized as zero, it would allow the admin to mint unlimited tokens.

Code snippet:

2.3 Follow good coding practice

Severity: Note.


  1. Missing docstrings.

Many functions in the code base lack documentation. This hinders reviewers’ understanding of the code’s intention, which is fundamental to correctly assess not only security, but also correctness. Additionally, docstrings improve readability and ease maintenance. They should explicitly explain the purpose or intention of the functions, the scenarios under which they can fail, the roles allowed to call them, the values returned, and the events emitted.

Consider thoroughly documenting all functions (and their parameters) that are part of the contracts’ public API. Functions implementing sensitive functionality, even if not public, should be clearly documented as well. When writing docstrings, consider following the Ethereum Natural Specification Format (NatSpec).

  1. Unspecific compiler version pragma

Contracts should be deployed with the same compiler version and flags that they have been tested the most with. Locking the pragma helps ensure that contracts do not accidentally get deployed using, for example, the latest compiler, which may have higher risks of undiscovered bugs. Contracts may also be deployed by others, and the pragma indicates the compiler version intended by the original authors.

2.4 Transfer function dependent on gas costs

Severity: Note.


Gas refers to the unit that measures the amount of computational effort required to execute specific operations on the Ethereum network. Since each Ethereum transaction requires computational resources to execute, each transaction requires a fee. Gas refers to the fee required to conduct a transaction on Ethereum successfully. Gas fees are paid in Ethereum’s native currency, ether (ETH). Gas prices are denoted in gwei, which itself is a denomination of ETH – each gwei is equal to 0.000000001 ETH (10-9 ETH).

Each opcode supported by the EVM has an associated gas cost. For example, SLOAD, which reads a word from storage, currently costs 200 gas. The gas costs aren’t arbitrary. They’re meant to reflect the underlying resources consumed by each operation on the nodes that make up Ethereum. Any smart contract that uses transfer() or send() is taking a hard dependency on gas costs by forwarding a fixed amount of gas: 2300.

In case when associated gas costs increase the function would fail to leave admin/users unable to withdraw or claim royalty from the contract leading to a denial of service (DoS).

Code snippet:


it is recommended to stop using the transfer() and send() in your code and switch to using call() instead. And follow the following protective measures to prevent re-entrancy attacks.

3. Security practices

4. Conclusion

The audited smart contract can be deployed. No security issues were found during the audit.

It is recommended to adhere to the security practices described in pt. 4 of this report to ensure the contract’s operability and prevent any issues that are not directly related to the code of this smart contract.

5. Revealing audit reports

Previous audit report:



Smart Contract Audits by Callisto Network.


Why Audit Smart Contracts?

Our Most Popular Audit Reports.


Trust the Blockchain, Audit the Smart Contracts.

Follow Callisto’s Security Department on Twitter to get our latest news and updates!