CVE-2021-40865Public exploitNetwork attack vector

Pre-authentication code execution via worker message deserialization

Published Oct 25, 2021 · Updated Aug 4, 2024

Unsafe deserialization in Apache Storm worker services allows remote attackers to execute arbitrary code before authentication. MessageDecoder handles a crafted -600 BackPressureStatus frame before SASL, then Kryo invokes Java ObjectInputStream on its payload without restricting types. Network access to a worker's Netty port is sufficient even when Storm authentication is enabled, and successful exploitation runs code in the worker JVM.

CVSS severity9.8
Critical
EPSS probability65.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in Apache Storm worker services allows remote attackers to execute arbitrary code before authentication. MessageDecoder handles a crafted -600 BackPressureStatus frame before SASL, then Kryo invokes Java ObjectInputStream on its payload without restricting types. Network access to a worker's Netty port is sufficient even when Storm authentication is enabled, and successful exploitation runs code in the worker JVM.

The record

CVE
CVE-2021-40865
Published
Oct 25, 2021
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Storm
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 25, 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?

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

  1. Affected versionversion=Apache Storm <v1.2.4 changes=[{"at":"v2.1.1","status":"unaffected"},{"at":"v2.2.1","status":"unaffected"},{"at":"v2.3.0","status":"unaffected"}]
  2. Affected versionversion=v1.0.0 <Apache Storm *

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Stormversion=Apache Storm <v1.2.4 changes=[{"at":"v2.1.1","status":"unaffected"},{"at":"v2.2.1","status":"unaffected"},{"at":"v2.3.0","status":"unaffected"}]; version=v1.0.0 <Apache Storm *

Published CVSS scores

9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

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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