CVE-2021-41264 json
UUPSUpgradeable vulnerability in OpenZeppelin Contracts
published 2021-09-15 5 y ago modified 2026-07-08 4 mo ago also GHSA-5vp3-v4hc-gx76 , EUVD-2021-1988
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.5%
- EPSS 1.5% chance of exploitation in 30 days, percentile 74%
- public exploits
- 0
- none known
Summary
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).
Patch / fix
- npm @openzeppelin/contracts 4.3.2
- npm @openzeppelin/contracts-upgradeable 4.3.2
- openzeppelin contracts 4.3.2
Exploit prediction
1.49% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 7.5 | AV:N/AC:L/Au:N/C:P/I:P/A:P |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | @openzeppelin/contracts | >=4.1.0, <4.3.2 |
4.3.2 |
| npm | @openzeppelin/contracts-upgradeable | >=4.1.0, <4.3.2 |
4.3.2 |
Affected products
- OpenZeppelin openzeppelin-contracts
Classification
- Weakness
-
- CWE-665 Improper Initialization
References
-
github.com
/OpenZeppelin/openzeppelin-contracts/commit/024cc50df478d2e8f78539819749e94d6df60592
web, patch, third-party-advisory
-
forum.openzeppelin.com
/t/security-advisory-initialize-uups-implementation-contracts/15301
web, issue-tracking, mitigation, patch, vendor-advisory
-
github.com
/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-5vp3-v4hc-gx76
web, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-41264
advisory
-
github.com
/OpenZeppelin/openzeppelin-contracts
package
Sources
- CVE List CVE-2021-41264
- GitHub Advisory GHSA-5vp3-v4hc-gx76
- NVD CVE-2021-41264
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.