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OpenAdvisories
High ALAS2023-2026-3136 2 CVEs

Important: composer security update (Amazon Linux 2023)

Published Sep 28, 2026 · Updated Sep 28, 2026

Summary

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-84361: 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. CVE-2026-59944: Package bin path can escape the package directory, bypassing the GHSA-gjfg-22fp-rrxx fix. A malicious or compromised Composer package could, when installed as a dependency, cause Composer to change the permissions of a file outside that package's own directory and to register a runnable vendor/bin command that points at that outside file. This is a path traversal and link following issue. It is not remote code execution, the attacker gains no ability to read or receive your data directly. The risk is that a file which was readable only by its owner, but modifiable by Composer, can be made world readable and executable, which is enough to expose its contents on a shared or multi tenant host. The earlier hardening from GHSA-gjfg-22fp-rrxx can be bypassed, since it only rejected literal .. path segments in a package's declared binaries, and was only applied in a single place during dependency resolution.

Fixed packages 1

ReleasePackageFixed in
Amazon Linux · 2023 composer 0:2.10.3-1.amzn2023.0.1

Vulnerabilities 2

  • High 7.7
    CVE-2026-84361 Public exploit

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

    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: P4…

  • Medium 6.1

    Composer: CVE-2026-59946 fix bypass via symlinked package bin path

    Composer is a dependency Manager for the PHP language. From 1.0 until 2.2.30 and from 2.3.0 until 2.10.3, a malicious or compromised dependency can bypass the earlier CVE-2026-59946 binary-path hardening because Composer validates literal parent-directory seg…

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-59944.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-84361.html