Packagist/composer/composer CVE-2026-40261: high 8.8, EPSS 1.69%

Composer has a command injection via malicious perforce reference

Action: Upgrade composer/composer to 2.2.27 or later.

composer require composer/composer:2.9.6

composer require composer/composer:2.2.27

Affected

Fixed versions

Sources

• osv: GHSA-gqw4-4w2p-838q
• https://github.com/composer/composer/security/advisories/GHSA-gqw4-4w2p-838q
• https://nvd.nist.gov/vuln/detail/CVE-2026-40261
• https://access.redhat.com/errata/RHSA-2026:8165
• https://access.redhat.com/security/cve/CVE-2026-40261
• https://bugzilla.redhat.com/show_bug.cgi?id=2458841
• https://github.com/FriendsOfPHP/security-advisories/blob/master/composer/composer/CVE-2026-40261.yaml
• https://github.com/composer/composer
• https://github.com/composer/composer/releases/tag/2.9.6
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40261.json

CVE-2026-40261 · published 2026-04-14T20:01:42Z · modified 2026-09-10T03:51:01.816745047Z · JSON