CVE-2023-34459 — OpenZeppelin Contracts is a library for smart contract development

OpenZeppelin Contracts is a library for smart contract development. Starting in version 4.7.0 and prior to version 4.9.2, when the `verifyMultiProof`, `verifyMultiProofCalldata`, `procesprocessMultiProof`, or `processMultiProofCalldat` functions are in use, it is possible to cons

01What is this vulnerability?

OpenZeppelin Contracts is a library for smart contract development. Starting in version 4.7.0 and prior to version 4.9.2, when the `verifyMultiProof`, `verifyMultiProofCalldata`, `procesprocessMultiProof`, or `processMultiProofCalldat` functions are in use, it is possible to construct merkle trees that allow forging a valid multiproof for an arbitrary set of leaves.

02Affected products

Vendor	Product	Versions
OpenZeppelin	openzeppelin	contracts — >= 4.7.0, < 4.9.2

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-06-16T22:13:18.181Z
• Last modified: 2024-12-16T18:35:27.231Z

09References

• github.com — https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-…
• github.com — https://github.com/OpenZeppelin/openzeppelin-contracts/commit/4d2383e17186be3e8c…
• github.com — https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.2