Public vulnerability disclosure

Open

CVE-2026-40176

Composer is vulnerable to Command Injection via Malicious Perforce Repository

publishedCWE-20CWE-78

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).

Technical severity7.8 highCVSS 3.1 · CNA: GitHub_M

Published2026-04-15Source updated 2026-11-02

Collected2026-11-034 attributed sources

Fixes and workarounds

Fix

RHSA-2026:8165: Red Hat Hardened Images

Source: ADP: redhat-SADP

Workaround

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: ADP: redhat-SADP

Fix

composer/composer (Packagist): OSV reports a fixed version 2.9.6. Check the advisory for supported release branches.

Source: OSV GHSA-wg36-wvj6-r67p

Fix

composer/composer (Packagist): OSV reports a fixed version 2.2.27. Check the advisory for supported release branches.

Source: OSV GHSA-wg36-wvj6-r67p

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
composer composer	>= 2.3, < 2.9.6 (affected) >= 1.0, < 2.2.27 (affected)	CNA: GitHub_M
Red Hat Hardened Images Red Hat `composer-main` https://access.redhat.com/downloads/content/package-browser/	≥ 2.9.7-1.hum1; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
composer/composer `composer/composer` Packagist	2.3.0 (affected, Packagist) 2.3.1 (affected, Packagist) 2.3.10 (affected, Packagist) 2.3.2 (affected, Packagist) 2.3.3 (affected, Packagist) 2.3.4 (affected, Packagist) 2.3.5 (affected, Packagist) 2.3.6 (affected, Packagist) 2.3.7 (affected, Packagist) 2.3.8 (affected, Packagist) 2.3.9 (affected, Packagist) 2.4.0 (affected, Packagist) 2.4.0-RC1 (affected, Packagist) 2.4.1 (affected, Packagist) 2.4.2 (affected, Packagist) 2.4.3 (affected, Packagist) 2.4.4 (affected, Packagist) 2.5.0 (affected, Packagist) 2.5.1 (affected, Packagist) 2.5.2 (affected, Packagist) 2.5.3 (affected, Packagist) 2.5.4 (affected, Packagist) 2.5.5 (affected, Packagist) 2.5.6 (affected, Packagist) 2.5.7 (affected, Packagist) 2.5.8 (affected, Packagist) 2.6.0 (affected, Packagist) 2.6.1 (affected, Packagist) 2.6.2 (affected, Packagist) 2.6.3 (affected, Packagist) 2.6.4 (affected, Packagist) 2.6.5 (affected, Packagist) 2.6.6 (affected, Packagist) 2.7.0 (affected, Packagist) 2.7.1 (affected, Packagist) 2.7.2 (affected, Packagist) 2.7.3 (affected, Packagist) 2.7.4 (affected, Packagist) 2.7.5 (affected, Packagist) 2.7.6 (affected, Packagist) 2.7.7 (affected, Packagist) 2.7.8 (affected, Packagist) 2.7.9 (affected, Packagist) 2.8.0 (affected, Packagist) 2.8.1 (affected, Packagist) 2.8.10 (affected, Packagist) 2.8.11 (affected, Packagist) 2.8.12 (affected, Packagist) 2.8.2 (affected, Packagist) 2.8.3 (affected, Packagist) 2.8.4 (affected, Packagist) 2.8.5 (affected, Packagist) 2.8.6 (affected, Packagist) 2.8.7 (affected, Packagist) 2.8.8 (affected, Packagist) 2.8.9 (affected, Packagist) 2.9.0 (affected, Packagist) 2.9.0-RC1 (affected, Packagist) 2.9.1 (affected, Packagist) 2.9.2 (affected, Packagist) 2.9.3 (affected, Packagist) 2.9.4 (affected, Packagist) 2.9.5 (affected, Packagist) Ecosystem version events: introduced 2.3.0; fixed 2.9.6 Source events (ECOSYSTEM) `[ { "introduced": "2.3.0" }, { "fixed": "2.9.6" } ]` Other versions: unaffected	OSV GHSA-wg36-wvj6-r67p
composer/composer `composer/composer` Packagist	1.0.0 (affected, Packagist) 1.0.1 (affected, Packagist) 1.0.2 (affected, Packagist) 1.0.3 (affected, Packagist) 1.1.0 (affected, Packagist) 1.1.0-RC (affected, Packagist) 1.1.1 (affected, Packagist) 1.1.2 (affected, Packagist) 1.1.3 (affected, Packagist) 1.10.0 (affected, Packagist) 1.10.0-RC (affected, Packagist) 1.10.1 (affected, Packagist) 1.10.10 (affected, Packagist) 1.10.11 (affected, Packagist) 1.10.12 (affected, Packagist) 1.10.13 (affected, Packagist) 1.10.14 (affected, Packagist) 1.10.15 (affected, Packagist) 1.10.16 (affected, Packagist) 1.10.17 (affected, Packagist) 1.10.18 (affected, Packagist) 1.10.19 (affected, Packagist) 1.10.2 (affected, Packagist) 1.10.20 (affected, Packagist) 1.10.21 (affected, Packagist) 1.10.22 (affected, Packagist) 1.10.23 (affected, Packagist) 1.10.24 (affected, Packagist) 1.10.25 (affected, Packagist) 1.10.26 (affected, Packagist) 1.10.27 (affected, Packagist) 1.10.28 (affected, Packagist) 1.10.3 (affected, Packagist) 1.10.4 (affected, Packagist) 1.10.5 (affected, Packagist) 1.10.6 (affected, Packagist) 1.10.7 (affected, Packagist) 1.10.8 (affected, Packagist) 1.10.9 (affected, Packagist) 1.2.0 (affected, Packagist) 1.2.0-RC (affected, Packagist) 1.2.1 (affected, Packagist) 1.2.2 (affected, Packagist) 1.2.3 (affected, Packagist) 1.2.4 (affected, Packagist) 1.3.0 (affected, Packagist) 1.3.0-RC (affected, Packagist) 1.3.1 (affected, Packagist) 1.3.2 (affected, Packagist) 1.3.3 (affected, Packagist) 1.4.0 (affected, Packagist) 1.4.1 (affected, Packagist) 1.4.2 (affected, Packagist) 1.4.3 (affected, Packagist) 1.5.0 (affected, Packagist) 1.5.1 (affected, Packagist) 1.5.2 (affected, Packagist) 1.5.3 (affected, Packagist) 1.5.4 (affected, Packagist) 1.5.5 (affected, Packagist) 1.5.6 (affected, Packagist) 1.6.0 (affected, Packagist) 1.6.0-RC (affected, Packagist) 1.6.1 (affected, Packagist) 1.6.2 (affected, Packagist) 1.6.3 (affected, Packagist) 1.6.4 (affected, Packagist) 1.6.5 (affected, Packagist) 1.7.0 (affected, Packagist) 1.7.0-RC (affected, Packagist) 1.7.1 (affected, Packagist) 1.7.2 (affected, Packagist) 1.7.3 (affected, Packagist) 1.8.0 (affected, Packagist) 1.8.1 (affected, Packagist) 1.8.2 (affected, Packagist) 1.8.3 (affected, Packagist) 1.8.4 (affected, Packagist) 1.8.5 (affected, Packagist) 1.8.6 (affected, Packagist) 1.9.0 (affected, Packagist) 1.9.1 (affected, Packagist) 1.9.2 (affected, Packagist) 1.9.3 (affected, Packagist) 2.0.0 (affected, Packagist) 2.0.0-RC1 (affected, Packagist) 2.0.0-RC2 (affected, Packagist) 2.0.0-alpha1 (affected, Packagist) 2.0.0-alpha2 (affected, Packagist) 2.0.0-alpha3 (affected, Packagist) 2.0.1 (affected, Packagist) 2.0.10 (affected, Packagist) 2.0.11 (affected, Packagist) 2.0.12 (affected, Packagist) 2.0.13 (affected, Packagist) 2.0.14 (affected, Packagist) 2.0.2 (affected, Packagist) 2.0.3 (affected, Packagist) 2.0.4 (affected, Packagist) 2.0.5 (affected, Packagist) 2.0.6 (affected, Packagist) 2.0.7 (affected, Packagist) 2.0.8 (affected, Packagist) 2.0.9 (affected, Packagist) 2.1.0 (affected, Packagist) 2.1.0-RC1 (affected, Packagist) 2.1.1 (affected, Packagist) 2.1.10 (affected, Packagist) 2.1.11 (affected, Packagist) 2.1.12 (affected, Packagist) 2.1.14 (affected, Packagist) 2.1.2 (affected, Packagist) 2.1.3 (affected, Packagist) 2.1.4 (affected, Packagist) 2.1.5 (affected, Packagist) 2.1.6 (affected, Packagist) 2.1.7 (affected, Packagist) 2.1.8 (affected, Packagist) 2.1.9 (affected, Packagist) 2.2.0 (affected, Packagist) 2.2.0-RC1 (affected, Packagist) 2.2.1 (affected, Packagist) 2.2.10 (affected, Packagist) 2.2.11 (affected, Packagist) 2.2.12 (affected, Packagist) 2.2.13 (affected, Packagist) 2.2.14 (affected, Packagist) 2.2.15 (affected, Packagist) 2.2.16 (affected, Packagist) 2.2.17 (affected, Packagist) 2.2.18 (affected, Packagist) 2.2.19 (affected, Packagist) 2.2.2 (affected, Packagist) 2.2.20 (affected, Packagist) 2.2.21 (affected, Packagist) 2.2.22 (affected, Packagist) 2.2.23 (affected, Packagist) 2.2.24 (affected, Packagist) 2.2.25 (affected, Packagist) 2.2.26 (affected, Packagist) 2.2.3 (affected, Packagist) 2.2.4 (affected, Packagist) 2.2.5 (affected, Packagist) 2.2.6 (affected, Packagist) 2.2.7 (affected, Packagist) 2.2.8 (affected, Packagist) 2.2.9 (affected, Packagist) Ecosystem version events: introduced 1.0.0; fixed 2.2.27 Source events (ECOSYSTEM) `[ { "introduced": "1.0.0" }, { "fixed": "2.2.27" } ]` Other versions: unaffected	OSV GHSA-wg36-wvj6-r67p

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

NVD applicability configurations (1)

These expressions retain AND/OR operators, negation, and required environmental products. A listed product is not sufficient to establish exposure when additional conditions apply.

[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:getcomposer:composer:*:*:*:*:*:*:*:*",
            "versionEndIncluding": "2.2.26",
            "versionStartIncluding": "1.0.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:getcomposer:composer:*:*:*:*:*:*:*:*",
            "versionEndIncluding": "2.9.5",
            "versionStartIncluding": "2.3.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 7.8 high	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`	CNA: GitHub_M
3.1 / 7.8 high	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`	ADP: redhat-SADP
3.1 / 7.8 high	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`	NVD: [email protected]
3.1 / 7.8 high	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`	NVD: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://github.com/composer/composer/security/advisories/GHSA-wg36-wvj6-r67pCNA: GitHub_M · x_refsource_CONFIRM
https://access.redhat.com/errata/RHSA-2026:8165CNA: GitHub_M · x_refsource_MISC
https://access.redhat.com/security/cve/CVE-2026-40176CNA: GitHub_M · x_refsource_MISC
https://bugzilla.redhat.com/show_bug.cgi?id=2458828CNA: GitHub_M · x_refsource_MISC
https://github.com/FriendsOfPHP/security-advisories/blob/master/composer/composer/CVE-2026-40176.yamlCNA: GitHub_M · x_refsource_MISC
https://github.com/composer/composer/releases/tag/2.2.27CNA: GitHub_M · x_refsource_MISC
https://github.com/composer/composer/releases/tag/2.9.6CNA: GitHub_M · x_refsource_MISC
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40176.jsonCNA: GitHub_M · x_refsource_MISC
https://access.redhat.com/security/cve/CVE-2026-40176ADP: redhat-SADP · vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2458828ADP: redhat-SADP · issue-tracking, x_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40176.jsonADP: redhat-SADP · x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:8165ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:8165[email protected]
https://access.redhat.com/security/cve/CVE-2026-40176[email protected]
https://bugzilla.redhat.com/show_bug.cgi?id=2458828[email protected]
https://github.com/FriendsOfPHP/security-advisories/blob/master/composer/composer/CVE-2026-40176.yaml[email protected]
https://github.com/composer/composer/releases/tag/2.2.27[email protected]
https://github.com/composer/composer/releases/tag/2.9.6[email protected] · Release Notes
https://github.com/composer/composer/security/advisories/GHSA-wg36-wvj6-r67p[email protected] · Vendor Advisory
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40176.json[email protected]
https://access.redhat.com/errata/RHSA-2026:81650b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-401760b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=24588280b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40176.json0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://github.com/advisories/GHSA-wg36-wvj6-r67pOSV / GitHub Security Advisories · advisory
https://osv.dev/vulnerability/GHSA-wg36-wvj6-r67pOSV / GitHub Security Advisories · osv

Prioritization

CISA known exploited vulnerabilities

No KEV listing in collected sources. This does not establish that exploitation is absent.

EPSS

1.04% estimated probability of exploitation in the next 30 days; percentile 64.15.
Assessed 2026-11-02 by FIRST.

SSVC

Exploitation: none
Automatable: no
Technical impact: total

ADP: CISA-ADP · 2026-04-16

Provenance

CNA: GitHub_M
Source updated 2026-11-02
Retrieved 2026-11-03

NVD
Source updated 2026-11-02
Retrieved 2026-11-03

OSV / GitHub Security Advisories
Source updated 2026-11-02
Retrieved 2026-11-03

FIRST EPSS
Source updated Not reported
Retrieved 2026-11-03

Disclosure revision
283d8d63dc506efa8b54d5fb15e0e4139a454959c873a1b9d7b4777ddffd8253

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