CVE-2021-38294Public exploitNetwork attack vector

Pre-auth code execution via unsanitized group lookup

Published Oct 25, 2021 · Updated Aug 4, 2024

Command injection in Apache Storm 1.x before 1.2.4 and 2.x before 2.2.1 allows remote attackers to execute code via Nimbus Thrift. ShellUtils.getGroupsForUserCommand concatenates the getTopologyHistory user value into bash -c commands that ShellBasedGroupsMapping executes without neutralizing metacharacters. Nimbus exposes the service on TCP port 6627, and default authentication is disabled, so network access is sufficient for code execution as the Nimbus process.

CVSS severity9.8
Critical
EPSS probability84.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Apache Storm 1.x before 1.2.4 and 2.x before 2.2.1 allows remote attackers to execute code via Nimbus Thrift. ShellUtils.getGroupsForUserCommand concatenates the getTopologyHistory user value into bash -c commands that ShellBasedGroupsMapping executes without neutralizing metacharacters. Nimbus exposes the service on TCP port 6627, and default authentication is disabled, so network access is sufficient for code execution as the Nimbus process.

The record

CVE
CVE-2021-38294
Published
Oct 25, 2021
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Storm
Classifications
CWE-74, CWE-78, T1190, T1059.004
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

7.5NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST National Vulnerability 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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1190Exploit Public-Facing Application
T1059.004Command and Scripting Interpreter: Unix Shell

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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