Composer is a dependency manager for PHP. In versions on the 2.x branch prior to 2.2.26 and 2.9.3, attackers controlling remote sources that Composer downloads from might in some way inject ANSI control characters in the terminal output of various Composer commands, causing mangled output and potentially leading to confusion or DoS of the terminal application. There is no proven exploit and this has thus a low severity but we still publish a CVE as it has potential for abuse, and we want to be on the safe side informing users that they should upgrade. Versions 2.2.26 and 2.9.3 contain a patch for the issue.
https://github.com/composer/composer/security/advisories/GHSA-59pp-r3rg-353g
https://github.com/composer/composer/releases/tag/2.9.3
https://github.com/composer/composer/releases/tag/2.2.26
https://github.com/composer/composer/commit/5db1876a76fdef76d3c4f8a27995c434c7a43e71
https://github.com/composer/composer/commit/1d40a95c9d39a6b7f80d404ab30336c586da9917
Published: 2025-12-30
Updated: 2025-12-31
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
Base Score: 5.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00017