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Not in CISA KEV
HIGH severity

Composer has a command injection via malicious perforce repositoryGHSA-wg36-wvj6-r67p

HIGH

GHSA-wg36-wvj6-r67p is a high-severity (CVSS 7.8) Improper Input Validation vulnerability in composer/composer. A fix is available for composer/composer — see the affected versions and patch details below.

Also known asBIT-composer-2026-40176CVE-2026-40176
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-wg36-wvj6-r67p.

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs64th percentile — riskier than 64% of all scored CVEsHighest risk
0.00%0.52%1.04%1.57%0.0%1.0%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected
🐘composer/composer🐘composer/composer

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The Perforce::generateP4Command() method constructed shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping. An attacker controlling a repository configuration in a malicious composer.json declaring a Perforce VCS repository could inject arbitrary commands through these values, leading to command execution in the context of the user running Composer. Composer would execute these injected commands even if Perforce is not installed.

VCS repositories are only loaded from the root composer.json file located in the directory you execute Composer commands in and from the composer config directory (e.g. ~/.config/composer/composer.json). So this vulnerability cannot be exploited through composer.json files of packages installed as dependencies.

You are at risk of command execution if you run Composer commands on untrusted projects with attacker supplied composer.json files, regardless of whether you or any of your dependencies use Perforce.

Patches

Fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline)

Workarounds

  • Carefully inspect composer.json files before running Composer on them. Verify that Perforce-related fields contain valid values.
  • Only run Composer commands on projects from trusted sources.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistcomposer/composer≥ 2.3.0&&< 2.9.62.9.6composer require composer/composer:^2.9.6
🐘Packagistcomposer/composer≥ 1.0.0&&< 2.2.272.2.27composer require composer/composer:^2.2.27

Affected Products

1 product · 2 configurations
Application
composergetcomposer
≥ 2.3.0 && ≤ 2.9.5
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for composer/composer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update composer/composer to 2.9.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wg36-wvj6-r67p is resolved across your whole dependency graph.

  3. Workarounds

    Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

To exploit this vulnerability, a user needs to run Composer commands on untrusted projects with attacker-supplied composer.json files. VCS repositories are only loaded from the root composer.json or the composer config directory, so this issue cannot be exploited through composer.json files of packages installed as…

Workaround published by Red Hat
To mitigate this vulnerability, only run Composer commands on projects from trusted sources. Also, inspect composer.json files before running Composer commands on them, specifically checking that Perforce-related fields contain valid values.
Source: Red Hat security advisory for GHSA-wg36-wvj6-r67p (CC BY 4.0)
ProductFixed inAdvisory
Red Hat Hardened Imagescomposer-main-2.9.7-1.hum1RHSA-2026:8165

Frequently Asked Questions

### Impact The `Perforce::generateP4Command()` method constructed shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping. An attacker controlling a repository configuration in a malicious composer.json declaring a Perforce VCS repository could inject arbitrary commands through these values, leading to command execution in the context of the user running Composer. Composer would execute these injected commands even if Perforce is not installed. VCS repositories are only loaded from the root composer.json file located in the dir
O3 Security · Impact-Aware SCA

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