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Go Ethereum CVE-2018-20421

HIGH
Allocation of Resources Without Limits or Throttling (CWE-770)
2018-12-24 cve@mitre.org
7.5
CVSS 3.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource allocation limits
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could exhaust system resources through uncontrolled allocation by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 1.5% exploitation probability (EPSS)

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AnalysisAI

Go Ethereum (aka geth) 1.8.19 allows attackers to cause a denial of service (memory consumption) by rewriting the length of a dynamic array in memory, and then writing data to a single memory. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Set resource limits, implement rate limiting, validate input sizes.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Allocation of Resources Without Limits (CWE-770), which allows attackers to exhaust system resources through uncontrolled allocation. Go Ethereum (aka geth) 1.8.19 allows attackers to cause a denial of service (memory consumption) by rewriting the length of a dynamic array in memory, and then writing data to a single memory location with a large index number, as demonstrated by use of "assembly { mstore }" followed by a "c[0xC800000] = 0xFF" assignment. Affected products include: Ethereum Go Ethereum.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

Go Ethereum (aka geth) 1.8.19 allows attackers to cause a denial of service (memory consumption) by rewriting the length of a dynamic array in memory, and then writing data to a single memory location with a large index number, as demonstrated by use of "assembly { mstore }" followed by a "c[0xC800000] = 0xFF" assignment.

Threat Intelligence Overview

EPSS Score
1.5%
Top 30% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 1.5%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

59
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +38
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:ethereum:go_ethereum:1.8.19:*:*:*:*:*:*:*
CVE-2022-23328 HIGH POC
7.5 Mar 04

A design flaw in all versions of Go-Ethereum allows an attacker node to send 5120 pending transactions of a high gas pri

CVE-2022-23327 HIGH POC
7.5 Mar 04

A design flaw in Go-Ethereum 1.10.12 and older versions allows an attacker node to send 5120 future transactions with a

CVE-2023-42319 HIGH POC
7.5 Oct 18

Geth (aka go-ethereum) through 1.13.4, when --http --graphql is used, allows remote attackers to cause a denial of servi

CVE-2018-19184 HIGH POC
7.5 Nov 12

cmd/evm/runner.go in Go Ethereum (aka geth) 1.8.17 allows attackers to cause a denial of service (SEGV) via crafted byte

CVE-2018-12018 HIGH POC
7.5 Jul 05

The GetBlockHeadersMsg handler in the LES protocol implementation in Go Ethereum (aka geth) before 1.8.11 may lead to an

CVE-2022-37450 MEDIUM POC
5.9 Aug 05

Go Ethereum (aka geth) through 1.10.21 allows attackers to increase rewards by mining blocks in certain situations, and

CVE-2026-26314 HIGH
7.5 Feb 19

Geth versions prior to 1.16.9 can be remotely crashed by sending a specially crafted message over the network, allowing

CVE-2026-22868 HIGH
7.5 Jan 13

Go Ethereum (geth) nodes can be remotely crashed through maliciously crafted network messages, causing denial of service

CVE-2026-22862 HIGH
7.5 Jan 13

Go Ethereum nodes can be remotely crashed by unauthenticated attackers sending specially crafted network messages, resul

CVE-2026-26313 HIGH
7.5 Feb 19

Go Ethereum versions up to 1.17.0 is affected by allocation of resources without limits or throttling (CVSS 7.5).

CVE-2026-26315 HIGH
7.5 Feb 19

Go Ethereum (Geth) versions prior to 1.16.9 contain a cryptographic implementation flaw in ECIES that allows remote atta

CVE-2023-40591 HIGH
7.5 Sep 06

go-ethereum (geth) is a golang execution layer implementation of the Ethereum protocol. Rated high severity (CVSS 7.5),

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