CVE-2021-39168: Openzeppelin Contracts

Critical severity, CVSS 9.8. EPSS: 1.6% chance of exploitation in the next 30 days.

OpenZepplin is a library for smart contract development. In affected versions a vulnerability in TimelockController allowed an actor with the executor role to escalate privileges. Further details about the vulnerability will be disclosed at a later date. As a workaround revoke the executor role from accounts not strictly under the team's control. We recommend revoking all executors that are not also proposers. When applying this mitigation, ensure there is at least one proposer and executor remaining.

Affected products

• Openzeppelin Contracts: from 3.3.0, before 3.4.2 (fixed in 3.4.2); from 4.0.0, before 4.3.1 (fixed in 4.3.1)

Published 2021-08-27. Last modified 2026-06-17.