OpenZeppelin Contracts initializer reentrancy may lead to double initialization
Moderate severity
GitHub Reviewed
Published
Dec 14, 2021
in
OpenZeppelin/openzeppelin-contracts
•
Updated Jan 28, 2023
Description
Reviewed
Dec 14, 2021
Published to the GitHub Advisory Database
Dec 14, 2021
Published by the National Vulnerability Database
Nov 4, 2022
Last updated
Jan 28, 2023
Impact
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.
Patches
A fix is included in the version v4.4.1 of
@openzeppelin/contracts
and@openzeppelin/contracts-upgradeable
.Workarounds
Avoid untrusted external calls during initialization.
References
OpenZeppelin/openzeppelin-contracts#3006
Credits
This issue was identified and reported by @chaitinblockchain through our bug bounty on Immunefi.
For more information
If you have any questions or comments about this advisory, or need assistance executing the mitigation, email us at [email protected].
References