CVE-2020-19765Network attack vector

Contract-state modification via inheritable reentrancy guard

Published Sep 7, 2021 · Updated Aug 4, 2024

Reentrancy in the Accounting 1.0 Ethereum contract allows remote attackers to alter contract state through inherited contract code. The noReentrance() modifier relies on an internal _in flag that an inheriting contract can reset, defeating the guard during nested execution. Network access without authentication is sufficient, but the public report does not identify the specific state changes or assets exposed.

CVSS severity7.5
High
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reentrancy in the Accounting 1.0 Ethereum contract allows remote attackers to alter contract state through inherited contract code. The noReentrance() modifier relies on an internal _in flag that an inheriting contract can reset, defeating the guard during nested execution. Network access without authentication is sufficient, but the public report does not identify the specific state changes or assets exposed.

The record

CVE
CVE-2020-19765
Published
Sep 7, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-863
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization

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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