CVE-2021-41264UUPSUpgradeable vulnerability in OpenZeppelin Contracts
- 9.8CriticalCVSS base score
- 1.5%Exploitation in 30 daysEPSS · top 26% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
OpenZeppelin Contracts is a library for smart contract development. In affected versions upgradeable contracts using `UUPSUpgradeable` may be vulnerable to an attack affecting uninitialized implementation contracts. A fix is included in version 4.3.2 of `@openzeppelin/contracts` and `@openzeppelin/contracts-upgradeable`. For users unable to upgrade; initialize implementation contracts using `UUPSUpgradeable` by invoking the initializer function (usually called `initialize`). An example is provided [in the forum](https://forum.openzeppelin.com/t/security-advisory-initialize-uups-implementation-contracts/15301).
Timeline
ID reserved
By GitHub_M
- 58 days later
· 58 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 1.5% · top 26% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
OpenZeppelin · openzeppelin-contracts
- affected >= 4.1.0 < 4.3.2
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npm@openzeppelin/contractsGHSA-5vp3-v4hc-gx76 (opens in a new tab)
- npm@openzeppelin/contracts-upgradeableGHSA-5vp3-v4hc-gx76 (opens in a new tab)
References
References3
- https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-5vp3-v4hc-gx76 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/OpenZeppelin/openzeppelin-contracts/commit/024cc50df478d2e8f78539819749e94d6df60592 (opens in a new tab)x_refsource_MISCx_transferred
- https://forum.openzeppelin.com/t/security-advisory-initialize-uups-implementation-contracts/15301 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-1988 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-5vp3-v4hc-gx76 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-41264)Record last updated .