CVE-2026-84361highCWE-78

CVE-2026-84361: high-severity vulnerability in composer

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

Published · Updated

41Vexday Risk Score

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

ssvc Attendcvss 7.7epss 0.5%
from disclosure to weapon1 days
Published on NVDSep 1
1st PoC+1d
exploitation probability
0.5%top 58% 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.
Related CVEs — composer

In the same product, most dangerous first.

CVE-2021-29472HIGHMissing argument delimiter can lead to code execution via VCS repository URLs or source download URLs on systems with Mercurial in composerEPSS 4.8%CVE-2024-35242HIGHComposer vulnerable to command injection via malicious git/hg branch namesEPSS 3.3%CVE-2021-41116HIGHCommand injection in composer on WindowsEPSS 2.8%CVE-2026-40261HIGHComposer has Command Injection via Malicious Perforce ReferenceEPSS 1.9%CVE-2022-24828HIGHMissing input validation can lead to command execution in composerEPSS 1.9%CVE-2023-43655MEDIUMRemote Code Execution via web-accessible composer.pharEPSS 1.5%
References
https://github.com/composer/composer/commit/0aac50528e83ed635cf788333635897469440220https://github.com/composer/composer/commit/199ad81a9cc6a2a5164ad79a8da26b2e19e521afhttps://github.com/composer/composer/releases/tag/2.10.3https://github.com/composer/composer/releases/tag/2.2.30https://github.com/composer/composer/security/advisories/GHSA-rvx4-ffvw-m9q3