How severe is CVE-2023-23940?

CVE-2023-23940 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability low.

Is CVE-2023-23940 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-23940?

CVE-2023-23940 affects Openzeppelin Contracts. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-23940?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2023-23940 published?

CVE-2023-23940 was published on 2023-02-03 and last updated on 2026-06-17.

CVE-2023-23940

CVE-2023-23940 is a medium-severity vulnerability in Openzeppelin Contracts with a CVSS 3.x base score of 6.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

Severity: Medium (CVSS 3.x base score 6.4)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Openzeppelin Contracts
Published: 2023-02-03
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2023-23940?: 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.
How severe is CVE-2023-23940?: CVE-2023-23940 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability low.
Is CVE-2023-23940 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-23940?: CVE-2023-23940 affects Openzeppelin Contracts. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-23940?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-23940 published?: CVE-2023-23940 was published on 2023-02-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:openzeppelin:contracts:*:*:*:*:*:cairo:*:*

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