Is there a public exploit for CVE-2026-40176?

Yes. Proof-of-concept code for CVE-2026-40176 has been published publicly.

Is there a proof of concept for CVE-2026-40176?

Yes — 3 proof-of-concept entries are linked on this page, from public repositories and community submissions. They are listed for authorised testing only.

How severe is CVE-2026-40176?

CVE-2026-40176 scores CVSS 7.8 (v3.1), rated high. EPSS puts the chance of exploitation in the next 30 days at 1.04%.

What does CVE-2026-40176 affect?

CVE-2026-40176 affects composer composer.

7.8 High

Composer is a dependency manager for PHP.

CVE-2026-40176

Composer is a dependency manager for PHP. Versions 1.0 through 2.2.26 and 2.3 through 2.9.5 contain a command injection vulnerability in the Perforce::generateP4Command() method, which constructs shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping. An attacker can inject arbitrary commands through these values in a malicious composer.json declaring a Perforce VCS repository, leading to command execution in the context of the user running Composer, even if Perforce is not installed. VCS repositories are only loaded from the root composer.json or the composer config directory, so this cannot be exploited through composer.json files of packages installed as dependencies. Users are at risk if they run Composer commands on untrusted projects with attacker-supplied composer.json files. This issue has been fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline).

Proof-of-concept code is published

Public PoC

Public PoCSaku0512/CVE-2026-40176-poc2 stars
Public PoCdaptheHuman/cve-2026-40176-cve-2026-40261
Public PoCikarolaborda/CVE-2026-40176

Signals come from Exploit-DB, Metasploit, Nuclei and published proof-of-concept repositories. Their absence means nothing was found, not that nothing exists.

Assessment

CVSS: 7.8 (v3.1)
Severity: High
EPSS: 1.04% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Public PoC
Published: 15 April 2026
Last updated: 2 November 2026
Affected: composer · composer
Assigner: GitHub_M

CVSS vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

At the source

EUVD (ENISA)

References

Community proofs of concept

No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.

Submit a proof of concept

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Query this programmatically

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