CVE-2021-29472Public exploitNetwork attack vector

Command execution via Mercurial option injection

Published Apr 27, 2021 · Updated Aug 3, 2024

Command injection in Composer before 1.10.22 and 2.0 through 2.0.12 allows attackers to execute commands via crafted Mercurial URLs. HgDriver and HgDownloader pass attacker-controlled URLs as command arguments without an option delimiter, allowing Mercurial configuration options to redefine a subcommand as an operating-system command. Exploitation requires Mercurial and control of a root project URL, a trusted repository's source URL, or input accepted by a Composer-based service; commands run with the Composer process's privileges.

CVSS severity8.8
High
EPSS probability4.66%
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 1.10.22 and 2.0 through 2.0.12 allows attackers to execute commands via crafted Mercurial URLs. HgDriver and HgDownloader pass attacker-controlled URLs as command arguments without an option delimiter, allowing Mercurial configuration options to redefine a subcommand as an operating-system command. Exploitation requires Mercurial and control of a root project URL, a trusted repository's source URL, or input accepted by a Composer-based service; commands run with the Composer process's privileges.

The record

CVE
CVE-2021-29472
Published
Apr 27, 2021
Updated
Aug 3, 2024
Vendor
Composer
Product
Composer
Classifications
CWE-141, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=< 1.10.22
  2. Affected versionversion=>=2.0,<2.0.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Composer · Composerversion=< 1.10.22; version=>=2.0,<2.0.13

Published CVSS scores

8.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-141Improper Neutralization of Parameter/Argument Delimiters
T1059Command and Scripting Interpreter

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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