CVE-2026-84361
HighCVSS 7.7Exploitation Probability (EPSS)
Low risk34th percentile - higher than 34% of all known CVEs
Summary
Composer, a dependency manager for PHP, has a vulnerability in versions from 1.0 to 2.2.30 and 2.10.3. A malicious package from a custom repository or an untrusted composer.lock file can set source.type to perforce and source.url to a P4PORT value starting with rsh: or jsh:. When the Perforce p4 client is installed and Composer installs the package from source, p4 executes a local command with the privileges of the user or CI account.
Risk Assessment
An attacker can execute arbitrary local commands on a developer machine or CI environment, potentially leading to system compromise or data theft.
Recommendation
Update Composer to version 2.2.30 or 2.10.3 (or later). Avoid using untrusted repositories and composer.lock files.
Other vulnerabilities in Composer
See all- CVE-2026-59944Medium
Composer from 1.0 to 2.2.30 and from 2.3.0 to 2.10.3 allows a malicious or compromised dependency to bypass the earlier binary-path hardening from CVE-2026-59946. Through an in-package symlink or installed.json metadata, an attacker can point to a binary path outside the installation directory, and Composer may change the external file's permissions and create a runnable vendor/bin proxy.
- CVE-2026-45793High
A vulnerability in Composer, a dependency manager for PHP, allows disclosure of GitHub OAuth tokens in error logs. Token validation using a regex rejects GITHUB_TOKEN values containing '-', and the rejected token is interpolated into an exception message, leading to leakage to stderr or CI logs.
- CVE-2026-59948High
A vulnerability in the Composer dependency manager for PHP allows an attacker to write files outside the vendor directory and project during package installation or update. The issue occurs when a package from an untrusted repository (other than Packagist.org or Private Packagist) uses an invalid name that is not properly validated before dependency-resolution results are written.
- CVE-2026-59947Medium
Composer, a dependency manager for PHP, prior to versions 2.2.29 and 2.10.2 leaked credentials (e.g., GitHub tokens) to debug output when run with -vvv verbosity. The issue was due to missing sanitization of username-only URL credentials.
- CVE-2026-59946Medium
A vulnerability in the Composer dependency manager for PHP allows changing permissions of an existing host file to world-readable and world-executable. The issue occurs during package install, update, or require when a package bin entry contains '..' path segments.
- CVE-2026-40261High
Composer versions 1.0 through 2.2.26 and 2.3 through 2.9.5 contain a command injection vulnerability in the Perforce::syncCodeBase() and Perforce::generateP4Command() methods. An attacker can inject arbitrary commands through crafted source reference or source url values containing shell metacharacters, even if Perforce is not installed.
- CVE-2026-40176High
Command injection vulnerability in the Perforce::generateP4Command() method in Composer, a dependency manager for PHP. An attacker can inject arbitrary commands through Perforce connection parameters (port, user, client) in a malicious composer.json, leading to command execution in the context of the user running Composer.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS