CVE-2026-40261

NameCVE-2026-40261
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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
composer (PTS)bullseye (security), bullseye2.0.9-2+deb11u4vulnerable
bookworm2.5.5-1+deb12u3vulnerable
bookworm (security)2.5.5-1+deb12u2vulnerable
trixie2.8.8-1+deb13u1vulnerable
forky, sid2.9.7-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
composersource(unstable)2.9.7-1

Notes

[trixie] - composer <no-dsa> (Minor issue; can be fixed via point release)
[bookworm] - composer <no-dsa> (Minor issue; can be fixed via point release)
https://github.com/composer/composer/security/advisories/GHSA-gqw4-4w2p-838q

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