What’s Vulnerable › Vulnerabilities

CVE-2023-23940: OpenZeppelin Contracts for Cairo is vulnerable to signature validation bypass

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-02-03 · updated 2026-06-17
• Weakness: CWE-345

Description

OpenZeppelin Contracts for Cairo is a library for secure smart contract development written in Cairo for StarkNet, a decentralized ZK Rollup. `is_valid_eth_signature` is missing a call to `finalize_keccak` after calling `verify_eth_signature`. As a result, any contract using `is_valid_eth_signature` from the account library (such as the `EthAccount` preset) is vulnerable to a malicious sequencer. Specifically, the malicious sequencer would be able to bypass signature validation to impersonate an instance of these accounts. The issue has been patched in 0.6.1.

Affected products

• openzeppelin-contracts: from 0.2.0 before 0.6.1 — fixed in 0.6.1

How to fix

Upgrade to a fixed version: openzeppelin-contracts 0.6.1. Check the vendor advisory for mitigations.

References

• https://github.com/OpenZeppelin/cairo-contracts/pull/542/commits/6d4cb750478fca2fd916f73297632f899aca9299
• https://github.com/OpenZeppelin/cairo-contracts/security/advisories/GHSA-626q-v9j4-mcp4
• https://github.com/OpenZeppelin/cairo-contracts/pull/542/commits/6d4cb750478fca2fd916f73297632f899aca9299
• https://github.com/OpenZeppelin/cairo-contracts/security/advisories/GHSA-626q-v9j4-mcp4

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