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High

Composer's missing argument delimiter can lead to code execution via VCS repository URLs or source download URLs on systems with Mercurial

  • Disclosed: 29.04.2021
  • Updated: 11.10.2026 10:22

URLs for Mercurial repositories in the root composer.json and package source download URLs are not sanitized correctly. Specifically crafted URL values allow commands to be executed in the HgDriver if hg/Mercurial is installed on the system.

Impact

  • The impact to Composer users directly is limited as the composer.json file is typically under their own control and source download URLs can only be supplied by third party Composer repositories they explicitly trust to download and execute source code from, e.g. Composer plugins.
  • The main impact is to services passing user input to Composer, including Packagist.org and Private Packagist. This allowed users to trigger remote command injection. The vulnerability has been patched on Packagist.org and Private Packagist within 12h of receiving the initial vulnerability report and based on a review of logs, to the best of our knowledge, was not abused by anyone.
  • Other services/tools using VcsRepository/VcsDriver or derivatives may also be vulnerable and should upgrade their composer/composer dependency immediately

Patches

1.10.22 and 2.0.13 include patches for this issue.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package composer/composer < 1.10.22, >= 2.0.0-alpha1, < 2.0.13 1.10.22, 2.0.13

References

CVSS score 8.8/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-88, CWE-94
Platform
Composer
Package
composer/composer
Disclosed
29.04.2021
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-h5h8-pc6h-jvvx - CC BY 4.0

Vulnerability history: composer/composer

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (17) in the archive
Total entries
17
First → latest
04.2021 10.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 13
  • Medium 3
  • Low 1

Disclosures per year

Severity:
  1. Composer arbitrary command execution via a malicious package's Perforce source URL
    High CVE-2026-84361 >= 2.3.0, < 2.10.3, >= 1.0, < 2.2.30 2.10.3, 2.2.30
  2. Composer: Arbitrary file write outside vendor via malicious transitive package name
    High · 7.0 CVE-2026-59948 >= 2.3.0, < 2.10.2, >= 1.0.0, < 2.2.29 2.10.2, 2.2.29
  3. Github Actions issued GITHUB_TOKEN disclosure in GitHub Actions logs
    High · 7.5 CVE-2026-45793 >= 2.3.0, < 2.9.8, >= 2.0.0, < 2.2.28, >= 1.0, < 1.10.28 2.9.8, 2.2.28, 1.10.28
  4. Composer has a command injection via malicious perforce repository
    High · 7.8 CVE-2026-40176 >= 2.3.0, < 2.9.6, >= 1.0.0, < 2.2.27 2.9.6, 2.2.27
  5. Composer has a command injection via malicious perforce reference
    High · 8.8 CVE-2026-40261 >= 2.3.0, < 2.9.6, >= 1.0.0, < 2.2.27 2.9.6, 2.2.27
  6. Composer has a command injection via malicious git branch name
    High · 8.8 CVE-2024-35241 >= 2.0, < 2.2.24, >= 2.3, < 2.7.7 2.2.24, 2.7.7
  7. Composer has multiple command injections via malicious git/hg branch names
    High · 8.8 CVE-2024-35242 >= 2.0, < 2.2.24, >= 2.3, < 2.7.7 2.2.24, 2.7.7
  8. Composer code execution and possible privilege escalation via compromised InstalledVersions.php or installed.php
    High · 8.8 CVE-2024-24821 >= 2.0.0-alpha1, < 2.2.23, >= 2.3.0-rc1, < 2.7.0 2.2.23, 2.7.0
  9. Composer Remote Code Execution vulnerability via web-accessible composer.phar
    High · 8.8 CVE-2023-43655 < 1.10.27, >= 2.0.0, < 2.2.22, >= 2.3.0, < 2.6.4 1.10.27, 2.2.22, 2.6.4
  10. Composer allows cache poisoning from other projects built on the same host
    High · 8.8 CVE-2015-8371 < 1.0.0 1.0.0
  11. Missing input validation can lead to command execution in composer
    High · 8.3 CVE-2022-24828 < 1.10.26, >= 2.0, < 2.2.12, >= 2.3, < 2.3.5 1.10.26, 2.2.12, 2.3.5
  12. Improper escaping of command arguments on Windows leading to command injection
    High · 8.2 CVE-2021-41116 < 1.10.23, >= 2.0.0-alpha1, < 2.1.9 1.10.23, 2.1.9
  13. Composer's missing argument delimiter can lead to code execution via VCS repository URLs or source download URLs on systems with Mercurial this entry
    High · 8.8 CVE-2021-29472 < 1.10.22, >= 2.0.0-alpha1, < 2.0.13 1.10.22, 2.0.13

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