Path Traversal in composer/composer (CVE-2026-59948)
Summary
Path traversal in composer/composer (CVE-2026-59948). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 2.2.29 or later.
Original description
The description as published by the source.
Composer is a dependency Manager for the PHP language. Prior to 2.2.29 and 2.10.2, a maliciously crafted package from an untrusted repository other than Packagist.org or Private Packagist can cause Composer to write attacker-controlled files outside the vendor directory and outside the project during install or update by using an invalid package name that is not correctly validated before dependency-resolution results are written or installed. This issue is fixed in versions 2.2.29 and 2.10.2.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-59948 has been found in composer/composer.
Successful exploitation can lead to full system takeover. CVSS score: 7.0/10.
What to do: upgrade composer/composer to 2.2.29 or later.
If unsure, ask your IT team or search "composer/composer CVE-2026-59948" on the vendor's site.
CVE-2026-59948 (composer/composer) — CWE-22 / CVSS v3 7.0
Attack vector: local / unauthenticated
Patched: 2.2.29 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in composer/composer.
Check the vendor advisory for the affected versions of composer/composer.
Severity: High (CVSS 7.0/10). Successful exploitation can lead to full system takeover.
Update to 2.2.29.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'composer/composer' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'composer/composer' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
composer/composerを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade composer/composer to 2.2.29ステージング環境で 2.2.29 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-59948 composer
- Ubuntu UBUNTU-CVE-2026-59948 composer
References
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web nvd.nist.gov
- web github.com