CVE-2023-23940Network attack vector

Account impersonation via unfinalized Keccak signature verification

Published Feb 3, 2023 · Updated Mar 10, 2025

Signature verification bypass in OpenZeppelin Contracts for Cairo 0.2.0 through 0.6.0 allows attackers to impersonate affected accounts. The is_valid_eth_signature function calls verify_eth_signature without finalizing the Keccak hint, allowing a dishonest executor to inject an incorrect hash result. Exploitation requires control of a Starknet sequencer or prover; successful validation bypass grants transaction-signing authority as the affected account.

CVSS severity6.4
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Signature verification bypass in OpenZeppelin Contracts for Cairo 0.2.0 through 0.6.0 allows attackers to impersonate affected accounts. The is_valid_eth_signature function calls verify_eth_signature without finalizing the Keccak hint, allowing a dishonest executor to inject an incorrect hash result. Exploitation requires control of a Starknet sequencer or prover; successful validation bypass grants transaction-signing authority as the affected account.

The record

CVE
CVE-2023-23940
Published
Feb 3, 2023
Updated
Mar 10, 2025
Vendor
OpenZeppelin
Product
OpenZeppelin Contracts for Cairo
Classifications
CWE-345, CWE-347
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.2.0, < 0.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenZeppelin · OpenZeppelin Contracts for Cairoversion=>= 0.2.0, < 0.6.1

Published CVSS scores

6.4GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L
5.3NISTCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity
CWE-347Improper Verification of Cryptographic Signature

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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