Bug 2458828 (CVE-2026-40176)

Summary: CVE-2026-40176 composer: command injection via malicious Perforce repository definition
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Composer. `Perforce::generateP4Command()` constructs shell commands by interpolating user-supplied Perforce connection parameters (port, user, client) without proper escaping, allowing an attacker to inject arbitrary commands through these values in a malicious composer.json declaring a Perforce VCS repository.
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Bug Depends On: 2459010, 2459011    
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Description OSIDB Bzimport 2026-04-15 21:01:11 UTC 
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).