# CVE-2026-84361: Composer: Perforce source URL permits P4PORT `rsh:` command execution > A malicious package can execute arbitrary commands via Perforce source URLs if the p4 client is installed, allowing attackers to run code with user privileges. - **Severity:** High 7.7 (`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`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 1 Sep 2026 - **Updated:** 3 Sep 2026 - **Also known as:** BIT-composer-2026-84361, DEBIAN-CVE-2026-84361, GHSA-rvx4-ffvw-m9q3, MINI-3hjh-7xq3-45jr, MINI-5hm4-49pw-qc98, SUSE-SU-2026:23635-1, SUSE-SU-2026:4059-1, UBUNTU-CVE-2026-84361, openSUSE-SU-2026:11689-1, openSUSE-SU-2026:21778-1 ## What is CVE-2026-84361? CVE-2026-84361 is a high-severity command injection vulnerability in composer, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official description 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. Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command) ## Which versions are affected by CVE-2026-84361? 5 open source packages ship an affected version, including composer/composer and composer. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `composer/composer` | Packagist | From 1.0 | 2.2.30 | | `composer/composer` | Packagist | From 1.0 | 2.2.30 | | `composer/composer` | Packagist | From 2.3.0 | 2.10.3 | | `composer/composer` | Packagist | From 2.3.0 | 2.10.3 | | `composer` | Bitnami | From 1.0.0 | 2.2.30, 2.10.3 | | `php-composer2` | SUSE:Linux Enterprise Module for Web and Scripting 15 SP7 | All versions | 2.6.4-150600.3.18.1 | | `php-composer2` | SUSE:Linux Enterprise Server 15 SP6-LTSS | All versions | 2.6.4-150600.3.18.1 | | `php-composer2` | SUSE:Linux Enterprise Server 16.0 | All versions | 2.8.9-160000.5.1 | | `php-composer2` | SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | All versions | 2.6.4-150600.3.18.1 | | `php-composer2` | SUSE:Linux Enterprise Server for SAP applications 16.0 | All versions | 2.8.9-160000.5.1 | | `php-composer2` | openSUSE:Leap 16.0 | All versions | 2.8.9-160000.5.1 | | `php-composer2` | openSUSE:Tumbleweed | All versions | 2.10.3-2.1 | ## How do I fix CVE-2026-84361? Upgrade composer/composer to a fixed version for your release line: 2.2.30 or 2.10.3. ## Is CVE-2026-84361 being exploited? There is no known exploitation of CVE-2026-84361 in the wild and no public exploit code. Public exploit code: - https://github.com/Saku0512/CVE-2026-84361-poc (github_poc): https://github.com/Saku0512/CVE-2026-84361-poc ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-84361 and fix it if it is affected. What it is: CVE-2026-84361 is a high-severity command injection vulnerability in composer, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2026-84361 in the wild and no public exploit code. Affected packages and fixed versions: - composer/composer (Packagist): affected from 1.0; fixed in 2.2.30 - composer/composer (Packagist): affected from 1.0; fixed in 2.2.30 - composer/composer (Packagist): affected from 2.3.0; fixed in 2.10.3 - composer/composer (Packagist): affected from 2.3.0; fixed in 2.10.3 - composer (Bitnami): affected from 1.0.0; fixed in 2.2.30, 2.10.3 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-84361/ (Markdown: https://insights.sbomify.com/CVE-2026-84361/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-84361 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-84361 - OSV: https://osv.dev/vulnerability/CVE-2026-84361 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-84361/ Summaries are generated and may contain mistakes; the official description above is the record.