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

Description

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 segments only during dependency resolution, while the symlink and installed-metadata paths described by the advisory skip that validation. A package can ship an in-package binary symlink that resolves outside its installation directory, or attacker-influenced vendor/composer/installed.json metadata can provide an escaping binary path during a reinstall or regeneration of missing vendor/bin entries. The installed-metadata path is reachable only when the vendor directory was not populated by the same validated install run, such as when it is restored from an untrusted cache, copied from an earlier build stage, carried over from an older Composer run, or writable by a lower-trust build step. Composer can follow the path, change the external target's permissions to make it world-readable and executable, and create a runnable vendor/bin proxy to that external file. The issue does not directly read or transmit data and does not by itself provide remote code execution. This issue is fixed in versions 2.2.30 and 2.10.3.

Scores

EPSS (exploitation in 30 days)

0.47% · top 59% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.1.

Weakness

• CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (opens in a new tab)All about CWE-22 and its CVEs
• CWE-59: Improper Link Resolution Before File Access ('Link Following') (opens in a new tab)All about CWE-59 and its CVEs

Affected products

• composer · composer

  • affected >= 1.0.0, < 2.2.30
  • affected >= 2.3.0, < 2.10.3

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Packagistcomposer/composerGHSA-96h3-5x6v-m776 (opens in a new tab)

References (5)

• https://github.com/composer/composer/security/advisories/GHSA-96h3-5x6v-m776 (opens in a new tab)x_refsource_CONFIRM
• https://github.com/composer/composer/commit/53b8bb4c24697b2f00a18cf1ef35a10392701b89 (opens in a new tab)x_refsource_MISC
• https://github.com/composer/composer/commit/ad649fdfdf8ed826d4a34e0e5690c76a0b4833aa (opens in a new tab)x_refsource_MISC
• https://github.com/composer/composer/releases/tag/2.10.3 (opens in a new tab)x_refsource_MISC
• https://github.com/composer/composer/releases/tag/2.2.30 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-96h3-5x6v-m776 (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-59944](https://trackcve.app/badge/CVE-2026-59944.svg)](https://trackcve.app/cve/CVE-2026-59944)

Record last updated 16 Sept 2026, 17:29 UTC.