Composer: Malicious Git or Hg Branch Names Can Run Code on composer install

Published as "Composer has multiple command injections via malicious git/hg branch names"

high Composer · Last reviewed Nov 10, 2026

CVE: CVE-2024-35242
GHSA: GHSA-v9qv-c7wm-wgmf
Packagist: PKSA-b8f7-zn44-r4gz
Reported: Jun 10, 2024

Lets an untrusted repository run commands on your machine when you clone it and run composer install inside it.

Affected and fixed versions

In composer/composer. Find the row for the version you run, and update to the release next to it.

If you run	Update to	Support
2.3 – 2.7.6	2.7.7	Supported

Show 1 older branch, no longer supported

2.0 – 2.2.23

2.2.24

Upgrade

Run the line for the branch you are on.

composer require composer/composer:^2.7.7

What this means

If you clone a repository someone else controls and run composer install inside it, specially crafted branch names in that repository can run commands on your machine. This is command injection: Composer didn't handle the branch names safely when it used them in commands.

See the Composer advisory and the fixes for 2.7 and 2.2 LTS.

Who is affected

Anyone running composer/composer who runs composer install inside a git or Mercurial (hg) repository they don't trust. The Composer team notes this requires cloning an untrusted repository first.

Running composer install in your own repositories, or ones you trust, isn't a risk from this flaw.

What to do

Update Composer to 2.7.7, or to 2.2.24 if you're on the 2.2 LTS line. Until you can, the Composer team's advice is to avoid cloning repositories that may be compromised.

A related advisory fixed in the same releases covers composer status, reinstall and remove on packages installed from git.

Check your app with an agent

Paste this into a coding agent that can read your project, such as Claude Code, Codex or Amp. It checks your composer.lock against the versions above and tells you what to update, without changing anything.

Check whether the PHP project you have access to is affected by this security advisory, and tell me what to update. Do a read-only check: don't edit files, don't run composer update or composer require, and don't try to reproduce the flaw.

Advisory: Composer: Malicious Git or Hg Branch Names Can Run Code on composer install (CVE-2024-35242, GHSA-v9qv-c7wm-wgmf)
Details: https://phpnews.net/security/composer/ghsa-v9qv-c7wm-wgmf

Affected versions, as Composer constraints:
- composer/composer: >=2.3,<2.7.7|>=2.0,<2.2.24

Fixed releases on branches that still get security fixes:
- 2.3 – 2.7.6: update to 2.7.7

1. Find every composer.lock in the project outside vendor/ (a monorepo can have one per app) and read the installed version of each package above. Packages installed as dependencies of other packages count too.
2. Compare each installed version with its constraint: "|" separates alternative ranges, and "," means both bounds apply.
3. For each affected install, read "What this means" at https://phpnews.net/security/composer/ghsa-v9qv-c7wm-wgmf and check whether the project meets the conditions it describes (a feature in use, a config value, a driver). Say which conditions you could check and which you couldn't.
4. Report a table: lock file | package | installed version | affected (yes, no or unknown) | conditions met (yes, no or unknown) | update to | evidence. For each affected package, give the command that would fix it, without running it: composer update <package> --with-dependencies when it is only installed as a dependency of another package, or composer require with the fixed version when composer.json requires it directly. If the installed version is on a branch with no fixed release listed, say it needs a move to a newer branch.

Sources

← All Composer advisories