CVE-2018-13202
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 · uneditedThe sell function of a smart contract implementation for MyBO, 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 confidenceThe MyBO Ethereum token smart contract's sell function contains an integer overflow vulnerability where the calculation 'amount * sellPrice' can result in zero due to arithmetic overflow. This causes sellers to receive zero or significantly reduced payouts while their tokens are deducted, effectively stealing their assets.
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 dataall versionsCVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the deployed contractQuery the contract address on-chain to retrieve its deployed bytecode or source code, and confirm it matches the Mybo token contract by comparing the contract name or verifying the deployment address from official Mybo sourcesAffected if The contract is the Mybo token with the vulnerable sell function
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Locate the sell function source codeIf source code is available on Etherscan or similar block explorers, navigate to the contract code and locate the 'sell' function that processes token salesAffected if The sell function contains the arithmetic expression 'amount * sellPrice' without proper overflow protection
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Check for SafeMath usageSearch the contract source code for 'SafeMath' library imports or usage, specifically looking at whether the multiplication in the sell function uses SafeMath.mul() or a similar safe arithmetic methodAffected if The contract does NOT use SafeMath for the amount * sellPrice calculation (plain multiplication is used) AND the Solidity version is below 0.8.0
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Verify Solidity compiler versionCheck the 'pragma solidity' declaration at the top of the contract source code to determine the compiler version usedAffected if The contract is compiled with Solidity version below 0.8.0 (versions 0.8.0+ have built-in overflow checks)
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Test with small sale amountIf you are a token holder, perform a small test sale with an amount that could trigger overflow (for example, a large amount combined with a sellPrice that would cause the product to overflow), and observe the payout receivedAffected if The seller receives zero or an unexpectedly small amount of Ether while their tokens are deducted
The environment is affected if the deployed Mybo token contract uses a Solidity version below 0.8.0 and the sell function performs 'amount * sellPrice' without SafeMath library protection, allowing an integer overflow to zero out the payout.
Generated from the published advisory. Verify against your own configuration.
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 dataReplace unsafe arithmetic operations with SafeMath library functions (for Solidity <0.8) or upgrade to Solidity 0.8+ which includes built-in overflow checks. Add explicit validation that the multiplication result is non-zero before processing the sale.
- Consultation4.0 h
- Implementation6.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2018-13202 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-13202 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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