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Extreme CoinApplication · Extreme Coin Project

CVE-2018-13221

HIGH · 7.5 CVSS v3.0 Published 2018-07-05
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 sell function of a smart contract implementation for Extreme Coin (XT) (Contract Name: ExtremeToken), an Ethereum token, has an integer overflow in which "amount * sellPrice" can be zero, consequently reducing a seller's assets.

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 sell function in the ExtremeToken smart contract contains an integer overflow vulnerability where the multiplication amount * sellPrice can overflow to zero due to insufficient bounds checking. When the product exceeds the maximum integer value, it wraps around to zero, causing the seller's assets to be incorrectly reduced to zero while the contract fails to transfer the correct payment.

MitigationReplace the vulnerable multiplication with SafeMath library functions (for Solidity <0.8) or upgrade to Solidity 0.8+ which includes built-in overflow checking. Deploy a new fixed contract version and migrate any stuck funds or token holders.

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
Extreme CoinApplication
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
High
Availability
None

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

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. Locate the deployed ExtremeToken contract
    Identify the contract address by checking the official Extreme Coin Project website, documentation, or blockchain explorers for the token contract address (commonly at token launch or in token listing pages)
    Affected if Unable to locate any deployed contract address - you may not be using the affected product
  2. Retrieve the contract source code or bytecode
    If the contract is verified on Etherscan or similar block explorer, view the source code. If not verified, use a blockchain explorer to view the contract bytecode
    Affected if No verified source code available and cannot inspect bytecode - verification is required to confirm vulnerability status
  3. Identify the sell function in the contract
    Search the source code for a function named 'sell', 'sellTokens', or similar that handles token selling/transferring tokens in exchange for ETH
    Affected if No sell function found - the contract may have been renamed or this may not be the vulnerable contract
  4. Check the multiplication pattern in the sell function
    Examine the arithmetic operation where the sell amount is calculated - look for 'amount * sellPrice' or equivalent multiplication without SafeMath or overflow protection
    Affected if The multiplication 'amount * sellPrice' exists without SafeMath library or Solidity 0.8+ - this indicates the vulnerability is present
  5. Verify SafeMath usage or Solidity version
    Check if the contract imports and uses SafeMath library for arithmetic operations, OR check the compiler version pragma directive (e.g., 'pragma solidity ^0.8.0')
    Affected if No SafeMath library used AND Solidity version is below 0.8 - the overflow vulnerability can be triggered

You are affected if the ExtremeToken sell function contains unprotected 'amount * sellPrice' multiplication without SafeMath and runs on Solidity below 0.8, allowing an attacker to trigger overflow and drain tokens.

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

Replace the vulnerable multiplication with SafeMath library functions (for Solidity <0.8) or upgrade to Solidity 0.8+ which includes built-in overflow checking. Deploy a new fixed contract version and migrate any stuck funds or token holders.

Fix this in Extreme Coin Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,500
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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-2018-13221 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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