Submit a Bug
20 April 2023
Live since
KYC required
Maximum bounty
10 April 2024
Last updated

Program Overview

Horizen technology offerings and crypto advisory services help organizations leverage the blockchain to solve a broad range of complex use cases. With deep experience in the crypto space, our passionate and committed team of blockchain experts, solution architects, product managers, and developers are accelerating the adoption of blockchain technology by focusing on the critical components of security, confidentiality, speed, and innovation. With unprecedented successes—including the ApeCoin launch—Horizen delivers value at scale. From crypto-native organizations seeking new monetization paths to companies transitioning to Web3, we deliver overwhelming value for both our partners and the entire crypto industry.

For more information about Horizen, please visit https://horizen.io/

For Whitehats: It is highly recommended that you review the details of this program in full. Although many Bug Bounty programs have standard terms and conditions, each also has their own unique details that are critical to your success.

Prior to submitting a report please review the Immunefi Bug Report Template and Best Practices.

Rewards by Threat Level

Please review how rewards are distributed based on the Immunefi Vulnerability Severity Classification System V2.2. This is a simplified 5-level scale system with separate scales for Smart Contracts and Websites/Apps.

Payouts and Payout Requirements:

Payouts are handled by the Horizen Labs team directly and are denominated in USD. However, payouts can be done in ZEN. Horizen Labs commits to honoring payouts according to the terms set out in this program at the time of report submission, and to treat this program as the agreement and source of truth concerning bug reports and responsible disclosures.

For the purposes of determining report validity, this is a Primacy of Impact program.

Learn more about report validity best practices here: Best Practice - Primacy of Impact vs Primacy of Rules.

Unlike other bug bounty programs on Immunefi, all bug report submissions, including associated vulnerabilities, become the exclusive property of Horizen. By making a submission to this program and in consideration for a bounty, the bug submitter conveys all ownership rights, titles, and interests in the bug report to Horizen. Thus, the final decision on whether a postmortem will be written is at the sole discretion of Horizen

KYC Requirements:

Horizen Labs does have a Know Your Customer (KYC) requirement for bug bounty payouts.

KYC Info Required:

Name, address, ID/passport, and a proof of residency

KYC information is only required on confirmation of the validity of a bug report.


USD $75,000
PoC Required
USD $25,000
PoC Required

Assets in scope

Impacts only apply to assets in active use by the project like contracts on mainnet or web/app assets used in production. Any impact that applies to assets not in active use, like test or mock files, are out-of-scope of the bug bounty program unless explicitly mentioned as in-scope.


Whitehats are highly encouraged to review any potential subdomains and what specific port(s) are in scope. Even though the domain may be the same, different ports may point to different assets.

Dev Environment and Documentation

Horizen Labs has included dev documentation and/or instructions to help in reviewing code and exploring for bugs:

Impacts to other assets

Hackers are encouraged to submit issues outside of the outlined Impacts and Assets in Scope.

If whitehats can demonstrate a critical impact on code in production for an asset not in scope, Horizen Labs encourages you to submit your bug report using the “primacy of impact exception” asset.

Impacts in Scope

(For Blockchain/DLTR and Smart Contracts Only) This program is considered to be governed by Primacy of Impact. For more information on what this means visit: Best Practice - Primacy of Impact vs Primacy of Rules.

Impacts are based on the Immunefi Vulnerability Severity Classification System V2.2.

At Immunefi, we classify bugs on a simplified 5-level scale:

  • Critical
  • High
  • Medium
  • Low
  • None

Only the following impacts are accepted within this bug bounty program. All other impacts are considered out-of-scope and ineligible for payout.

Impacts in scope

Only the following impacts are accepted within this bug bounty program. All other impacts are not considered as in-scope, even if they affect something in the assets in scope table.


  • Network not being able to confirm new transactions (Total network shutdown)
  • Unintended permanent chain split requiring hard fork (Network partition requiring hard fork)
  • Direct loss of funds
  • Permanent freezing of funds (fix requires hardfork)
  • Public RPC API crash
  • Unintended chain split (Network partition)
  • Transient consensus failures

Out of Scope & Rules

The following impacts and attack vectors are excluded from rewards by default for all Immunefi bug bounty programs:

  • Attacks that the reporter has already exploited themselves, leading to damage
  • Attacks requiring access to leaked keys/credentials
  • Attacks requiring access to privileged addresses (governance, strategist), except in such cases where the contracts are intended to have no privileged access to functions that make the attack possible
  • Broken link hijacking is out of scope

Smart Contracts and Blockchain/DLT

  • Basic economic governance attacks (e.g. 51% attack)
  • Lack of liquidity
  • Best practice critiques
  • Sybil attacks
  • Centralization risks


  • Any assets under Horizen mainnet are out of scope. Only Gobi and Horizen testnets are valid.
  • Any attack requiring the majority of the mining hashrate
  • Attacks requiring MITM or physical access to a user's device
  • Previously known vulnerable libraries without a working Proof of Concept.
  • Rate limiting or bruteforce issues on non-authentication / local endpoints (e.g., RPCs, websocket)
  • Application Flood Attacks on exposed ports

Prohibited Activities:

The following activities are prohibited by this bug bounty program. Violation of these rules can result in a temporary suspension or permanent ban from the Immunefi platform at the sole discretion of the Immunefi team, which may also result in: 1) the forfeiture and loss of access to all bug submissions, and 2) zero payout.

Please note that Immunefi has no tolerance for spam/low-quality/incomplete bug reports, “beg bounty” behavior, and misrepresentation of assets and severity. Immunefi exists to protect the global crypto community, not facilitate grift.


  • Any testing with mainnet or public testnet deployed code; all testing should be done on private testnets
  • Attempting phishing or other social engineering attacks against our employees and/or customers
  • Any testing with third party systems and applications (e.g. browser extensions) as well as websites (e.g. SSO providers, advertising networks)
  • Any denial of service attacks
  • Automated testing of services that generates significant amounts of traffic
  • Public disclosure of an unpatched vulnerability in an embargoed bounty
  • Any other actions prohibited by the Immunefi Rules. These rules are subject to change at any time.