title: OpenZeppelin Contracts initializer reentrancy may lead to double initialization
description: OpenZeppelin Contracts is a library for secure smart contract development. Before version 4.4.1 but after 3.2.0, initializer functions that are invoked separate from contract creation (the most prominent example being minimal proxies) may be reentered if they make an untrusted non-view external call. Once an initializer has finished running it can never be re-executed. However, an exception put in place to support multiple inheritance made reentrancy possible in the scenario described above, breaking the expectation that there is a single execution. Note that upgradeable proxies are commonly initialized together with contract creation, where reentrancy is not feasible, so the impact of this issue is believed to be minor. This issue has been patched, please upgrade to version 4.4.1. As a workaround, avoid untrusted external calls during initialization.
problem types: CWE-665: Improper Initialization
affected:
{
vendor: OpenZeppelin
product: openzeppelin-contracts
versions:
version: >= 3.2.0, < 4.4.1, status: affected
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
attackVector: NETWORK
attackComplexity: HIGH
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: LOW
integrityImpact: LOW
availabilityImpact: LOW
baseScore: 5.6
baseSeverity: MEDIUM
]