CVE-2021-43668

Persistent node crash via LevelDB nil dereference

Published Nov 18, 2021 · Updated Aug 4, 2024

Denial of service in Go-Ethereum 1.10.9 and earlier allows local users to crash a fast-sync node after prolonged fuzzed peer traffic. While reopening the chain database, LevelDB's table.Reader.newBlockIter dereferences a nil pointer and terminates Geth with SIGSEGV. The documented trigger required more than 24 hours of fuzzing in a private test network; the resulting state prevented node recovery.

CVSS severity5.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Go-Ethereum 1.10.9 and earlier allows local users to crash a fast-sync node after prolonged fuzzed peer traffic. While reopening the chain database, LevelDB's table.Reader.newBlockIter dereferences a nil pointer and terminates Geth with SIGSEGV. The documented trigger required more than 24 hours of fuzzing in a private test network; the resulting state prevented node recovery.

The record

CVE
CVE-2021-43668
Published
Nov 18, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 18, 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 vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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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