Composer has Command Injection via Malicious Perforce Reference

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Summary

CVECVE-2026-40261
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-15 21:17:27 UTC
Updated2026-04-17 15:38:09 UTC
DescriptionComposer 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::syncCodeBase() method, which appends the $sourceReference parameter to a shell command without proper escaping, and additionally in the Perforce::generateP4Command() method as in GHSA-wg36-wvj6-r67p / CVE-2026-40176, which interpolates user-supplied Perforce connection parameters (port, user, client) from the source url field without proper escaping. An attacker can inject arbitrary commands through crafted source reference or source url values containing shell metacharacters, even if Perforce is not installed. Unlike CVE-2026-40176, the source reference and url are provided as part of package metadata, meaning any compromised or malicious Composer repository can serve package metadata declaring perforce as a source type with malicious values. This vulnerability is exploitable when installing or updating dependencies from source, including the default behavior when installing dev-prefixed versions. This issue has been fixed in Composer 2.2.27 (2.2 LTS) and 2.9.6 (mainline). If developers are unable to immediately update, they can avoid installing dependencies from source by using --prefer-dist or the preferred-install: dist config setting, and only use trusted Composer repositories as a workaround.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from [email protected]

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

EPSS: 0.000330000 probability, percentile 0.093670000 (date 2026-04-18)

Problem Types: CWE-20 | CWE-78 | CWE-78 CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | CWE-20 CWE-20: Improper Input Validation

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Composer Composer affected >= 2.3.0, < 2.9.6 Not specified
CNA Composer Composer affected >= 1.0.0, < 2.2.27 Not specified

References

ReferenceSourceLinkTags
github.com/composer/composer/security/advisories/GHSA-gqw4-4w2p-838q [email protected] github.com
github.com/composer/composer/releases/tag/2.9.6 [email protected] github.com
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