CVE-2024-43366Public exploitNetwork attack vector

Contract misexecution via discarded loop bounds

Published Aug 15, 2024 · Updated Aug 16, 2024

Incorrect loop compilation in Matter Labs ZKsync Vyper Compiler 1.3.12 through 1.5.2 allows attackers to cause loss of funds via loop stops. The compiler discards Vyper's bound parameter when lowering range loops to the LLL repeat instruction, causing generated code to use a later exit condition. Exposure requires a contract compiled with the affected release and a variable-ended range loop whose extra iterations have consequences; common array iteration is unaffected, and no affected contracts were identified.

CVSS severity7.5
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect loop compilation in Matter Labs ZKsync Vyper Compiler 1.3.12 through 1.5.2 allows attackers to cause loss of funds via loop stops. The compiler discards Vyper's bound parameter when lowering range loops to the LLL repeat instruction, causing generated code to use a later exit condition. Exposure requires a contract compiled with the affected release and a variable-ended range loop whose extra iterations have consequences; common array iteration is unaffected, and no affected contracts were identified.

The record

CVE
CVE-2024-43366
Published
Aug 15, 2024
Updated
Aug 16, 2024
Vendor
Matter Labs
Product
ZKsync Vyper Compiler
Classifications
CWE-835
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 15, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 1.3.12, < 1.5.3
  2. Affected versionversion=1.3.12 <1.5.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Matter Labs · ZKsync Vyper Compilerversion=>= 1.3.12, < 1.5.3; version=1.3.12 <1.5.3

Published CVSS scores

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')

Public exploit references

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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