CVE-2021-43669Network attack vector

Orderer crashes via malformed request headers

Published Nov 18, 2021 · Updated Aug 4, 2024

Denial of service in Hyperledger Fabric before 2.4.0 allows remote attackers to crash orderers with a malformed Order request. The etcdraft Chain.isConfig method calls protoutil.ChannelHeader on the request envelope and panics when header extraction fails instead of returning the parse error. An unauthenticated network client that can submit a crafted request can terminate multiple orderers, interrupting ledger ordering.

CVSS severity7.5
High
EPSS probability1.13%
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 Hyperledger Fabric before 2.4.0 allows remote attackers to crash orderers with a malformed Order request. The etcdraft Chain.isConfig method calls protoutil.ChannelHeader on the request envelope and panics when header extraction fails instead of returning the parse error. An unauthenticated network client that can submit a crafted request can terminate multiple orderers, interrupting ledger ordering.

The record

CVE
CVE-2021-43669
Published
Nov 18, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-444, T1499
Attack vector
network
Privileges
unauthenticated

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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
T1499Endpoint Denial of Service

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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