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MegacryptopolisApplication

CVE-2018-13877

HIGH · 7.5 CVSS v3.0 Published 2018-08-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The doPayouts() function of the smart contract implementation for MegaCryptoPolis, an Ethereum game, has a Denial of Service vulnerability. If a smart contract that has a fallback function always causing exceptions buys a land, users cannot buy lands near that contract's land, because those purchase attempts will not be completed unless the doPayouts() function successfully sends Ether to certain neighbors.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The MegaCryptoPolis smart contract's doPayouts() function sends Ether to neighboring land owners during land purchases. If a neighboring land is owned by a contract with a fallback function that always throws/reverts, the payout fails and blocks all subsequent land purchases near that contract, causing a Denial of Service.

MitigationImplement a pull-payment pattern where payouts are recorded as pending balances rather than sent directly, allowing buyers to complete purchases even if some neighbor payouts fail, with affected neighbors able to withdraw their pending earnings later.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
MegacryptopolisApplication
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if MegaCryptoPolis contract is deployed in your environment
    Query the blockchain for the MegaCryptoPolis contract address. If running a node, use web3.eth.getCode() or similar API to check if contract code exists at the known contract address.
    Affected if No contract code is found at the expected MegaCryptoPolis address - you are not affected.
  2. Verify the doPayouts function exists in the deployed contract
    Retrieve and inspect the contract bytecode or source code. Look for the doPayouts function that handles Ether transfers to neighboring land owners.
    Affected if The doPayouts function is absent - you are not affected.
  3. Check land ownership records for contract-owned lands
    Query the contract's land ownership mapping to identify lands owned by contract addresses (non-EOA addresses). Look for lands where the owner is a smart contract.
    Affected if No neighboring lands are owned by smart contracts - you are not vulnerable to this specific attack vector.
  4. Inspect neighboring contract fallback functions
    For any contract-owned neighboring lands, retrieve the contract code and examine the fallback function. Check if it contains a require(), revert(), or assert() that always fails.
    Affected if The fallback function in neighboring contract-owned lands does not always revert - the payout mechanism can still succeed.
  5. Test a small land purchase near a contract-owned neighbor
    Attempt a test land purchase in the vicinity of a contract-owned neighboring land using a test transaction with limited value.
    Affected if The transaction reverts and blocks the purchase, preventing land transactions near that contract-owned neighbor - you ARE affected by CVE-2018-13877.

You are affected if the MegaCryptoPolis contract is deployed with the vulnerable doPayouts function and there exist neighboring lands owned by contracts with always-reverting fallback functions, causing purchase transactions to fail.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement a pull-payment pattern where payouts are recorded as pending balances rather than sent directly, allowing buyers to complete purchases even if some neighbor payouts fail, with affected neighbors able to withdraw their pending earnings later.

Fix this in Megacryptopolis Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-13877 in production — separate from our analysis above.

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What this is

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