title: Integer underflow in Frontier
description: Frontier is Substrate's Ethereum compatibility layer. Prior to commit number `8a93fdc6c9f4eb1d2f2a11b7ff1d12d70bf5a664`, a bug in Frontier's MODEXP precompile implementation can cause an integer underflow in certain conditions. This will cause a node crash for debug builds. For release builds (and production WebAssembly binaries), the impact is limited as it can only cause a normal EVM out-of-gas. Users who do not use MODEXP precompile in their runtime are not impacted. A patch is available in pull request #549.
problem types: CWE-191: Integer Underflow (Wrap or Wraparound)
affected:
{
product: frontier
vendor: paritytech
versions:
status: affected, version: < 8a93fdc
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 6.5
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]