CVE-2021-41116Network attack vector

Command execution via improper Windows argument escaping

Published Oct 5, 2021 · Updated Aug 4, 2024

Command injection in Composer before 1.10.23 and 2.0 through 2.1.8 allows remote attackers to execute commands via untrusted dependencies. ProcessExecutor::escapeArgument incorrectly quotes Windows shell metacharacters in dependency-derived arguments, allowing them to alter constructed commands. A Windows user must invoke Composer to install an attacker-controlled dependency; other systems and WSL are unaffected, and commands run with that user's privileges.

CVSS severity9.8
Critical
EPSS probability2.90%
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 Composer before 1.10.23 and 2.0 through 2.1.8 allows remote attackers to execute commands via untrusted dependencies. ProcessExecutor::escapeArgument incorrectly quotes Windows shell metacharacters in dependency-derived arguments, allowing them to alter constructed commands. A Windows user must invoke Composer to install an attacker-controlled dependency; other systems and WSL are unaffected, and commands run with that user's privileges.

The record

CVE
CVE-2021-41116
Published
Oct 5, 2021
Updated
Aug 4, 2024
Vendor
Composer
Product
Composer
Classifications
CWE-77, T1059.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 5, 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=< 1.10.23
  2. Affected versionversion=>= 2.0, < 2.1.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Composer · Composerversion=< 1.10.23; version=>= 2.0, < 2.1.9

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1059.003Command and Scripting Interpreter: Windows Command Shell

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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