UUPSUpgradeable vulnerability in @openzeppelin/contracts
Impact
Upgradeable contracts using UUPSUpgradeable may be vulnerable to an attack affecting uninitialized implementation contracts. We will update this advisory with more information soon.
Patches
A fix is included in version 4.3.2 of @openzeppelin/contracts and @openzeppelin/contracts-upgradeable.
Workarounds
Initialize implementation contracts using UUPSUpgradeable by invoking the initializer function (usually called initialize). An example is provided in the forum.
References
For more information
If you have any questions or comments about this advisory, or need assistance executing the mitigation, email us at security@openzeppelin.com.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @openzeppelin/contracts | >= 4.1.0, < 4.3.2 | 4.3.2 |
| npm package | @openzeppelin/contracts-upgradeable | >= 4.1.0, < 4.3.2 | 4.3.2 |
References
- https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-5vp3-v4hc-gx76
- https://nvd.nist.gov/vuln/detail/CVE-2021-41264
- https://github.com/OpenZeppelin/openzeppelin-contracts/commit/024cc50df478d2e8f78539819749e94d6df60592
- https://forum.openzeppelin.com/t/security-advisory-initialize-uups-implementation-contracts/15301
- https://github.com/OpenZeppelin/openzeppelin-contracts
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-665- Platform
- npm
- Package
@openzeppelin/contracts, @openzeppelin/contracts-upgradeable- Disclosed
- 15.09.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-5vp3-v4hc-gx76 - CC BY 4.0
Vulnerability history: @openzeppelin/contracts-upgradeable
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 22
- First → latest
- 08.2021 07.2025
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
- High 5
- Medium 12
- Low 2
Disclosures per year
- 2021: 5
- 2022: 8
- 2023: 7
- 2024: 1
- 2025: 1
- 2026: 0
-
UUPSUpgradeable vulnerability in @openzeppelin/contracts this entry
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