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CVE-2026-59948
high
CVSS 7.0
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. Exploitable via ``install``. Mitigation: upgrade to `2.2.29` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-59948** has been found in composer/composer.
Attackers can target a specific entry point like ``install`` over the network to misuse the product.
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
Attack surface: `install` / `update` / `authorized_keys` / `composer.lock`
Patched: `2.2.29` — apply immediately
Workaround: Do not use untrusted package repositories.
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.
❓ What is the problem
**Path traversal** (CWE-22) exists in composer/composer. Attackers reach the vulnerable code path via ``install`` without authentication.
📍 Affected scope
composer/composer — . Attack surface: `install` / `update` / `authorized_keys` / `composer.lock`.
🔥 Severity
Severity: High (CVSS 7.0/10). Successful exploitation can lead to full system takeover
🔧 How to fix
Update to **2.2.29**.
🛡️ Workaround
Workaround: Do not use untrusted package repositories.
🔍 Detection
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 (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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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。
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5Apply temporary workaround mitigate
Do not use untrusted package repositories.パッチが適用されるまでの応急処置として、Do not use untrusted package repositories. を実施。回避策の副作用 (機能低下) を確認した上で。
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6Apply 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と、Step 3 で見つけた異常検知の続報チェックを含めること。
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7Post-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 Step 3 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
composer
composer/composer
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.2.29"}]}]
References
- web https://github.com/composer/composer/commit/502c6c4f699802d9cf464728b3e8a95674f919a0
- web https://github.com/composer/composer/commit/c50b1efd13ebd73f6dca19b31424c5a02bf93cc1
- web https://github.com/composer/composer/releases/tag/2.10.2
- web https://github.com/composer/composer/releases/tag/2.2.29
- web https://github.com/composer/composer/security/advisories/GHSA-499r-g7pc-vmp9
- web https://nvd.nist.gov/vuln/detail/CVE-2026-59948
- web https://github.com/advisories/GHSA-499r-g7pc-vmp9