CVE-2026-84361highCWE-78

Composer: Perforce source URL permits P4PORT `rsh:` command execution

41Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 7.7epss 0.4%

from disclosure to weapon1 days

Published on NVDSep 1

1st PoC+1d

exploitation probability

0.4%top 66% of all CVEs

observed exploitation

nono source reports it

1 public exploit(s)

Composer is a dependency Manager for the PHP language. From 1.0 until 2.2.30 and 2.10.3, a malicious dependency package from a custom Composer repository or an untrusted composer.lock file could set source.type to perforce and source.url to an rsh: or jsh: P4PORT value. When the Perforce p4 client was installed and Composer installed the package from source through composer install or composer update, including --prefer-source, Composer\Util\Perforce passed the address to p4 without validation, causing p4 to run a local command with the privileges of the user or CI account. Packagist.org does not permit Perforce source metadata. This issue is fixed in versions 2.2.30 and 2.10.3.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Affected products

composer · composer

public PoCs found — 1

githubgithub.com/Saku0512/CVE-2026-84361-poc★ 0

⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.

References

https://github.com/composer/composer/commit/0aac50528e83ed635cf788333635897469440220 https://github.com/composer/composer/commit/199ad81a9cc6a2a5164ad79a8da26b2e19e521af https://github.com/composer/composer/releases/tag/2.10.3 https://github.com/composer/composer/releases/tag/2.2.30 https://github.com/composer/composer/security/advisories/GHSA-rvx4-ffvw-m9q3