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HIGH

CVE-2021-29472

CVSS v3

8.8

HIGH

EPSS Score

4.8 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • composerBitnamiall versions · fixed in 1.10.22
  • composer/composerPackagistfrom 2.0.0-alpha1 · fixed in 2.0.13

Vendor advisories

  • CVE-2021-29472 Red Hat Product Security

    composer: Specifically crafted URL values allow code to be executed in the HgDriver

Full record on NVD

Description

Composer is a dependency manager for PHP. URLs for Mercurial repositories in the root composer.json and package source download URLs are not sanitized correctly. Specifically crafted URL values allow code to be executed in the HgDriver if hg/Mercurial is installed on the system. 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 code execution. 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. Versions 1.10.22 and 2.0.13 include patches for this issue.

Technical details

Published
2021-04-27

Frequently asked questions

What is CVE-2021-29472?

Composer is a dependency manager for PHP. URLs for Mercurial repositories in the root composer.json and package source download URLs are not sanitized correctly. Specifically crafted URL values allow code to be executed in the HgDriver if hg/Mercurial is installed on the system. 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 code execution. 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. Versions 1.10.22 and 2.0.13 include patches for this issue.

Is CVE-2021-29472 actively exploited?

Active exploitation of CVE-2021-29472 has not been confirmed. Its EPSS score was 4.8% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-29472?

CVE-2021-29472 has a CVSS v3 base score of 8.8 (HIGH severity).

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