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CVE-2026-45793
high
CVSS 7.5
Information Disclosure in composer/composer (CVE-2026-45793)
Summary
vulnerability in composer/composer (CVE-2026-45793). Confidential information can be exposed externally. Exploitable via ``GITHUB_TOKEN``. Mitigation: upgrade to `1.10.28` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-45793** has been found in composer/composer.
Attackers can target a specific entry point like ``GITHUB_TOKEN`` over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade composer/composer to **1.10.28** or later.
If unsure, ask your IT team or search "composer/composer CVE-2026-45793" on the vendor's site.
CVE-2026-45793 (composer/composer) — CWE-200 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: `GITHUB_TOKEN` / `ghp_` / `UnexpectedValueException` / `main`
Patched: `1.10.28` — 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.
❓ What is the problem
**information disclosure** (CWE-200) exists in composer/composer. Attackers reach the vulnerable code path via ``GITHUB_TOKEN`` without authentication.
📍 Affected scope
composer/composer — . Attack surface: `GITHUB_TOKEN` / `ghp_` / `UnexpectedValueException` / `main`.
🔥 Severity
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally
🔧 How to fix
Update to **1.10.28**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 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
-
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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6Apply patch patch
Upgrade composer/composer to 1.10.28ステージング環境で 1.10.28 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":"1.10.28"}]}]
Packagist
composer/composer
[{"type":"ECOSYSTEM","events":[{"introduced":"1.0"},{"fixed":"1.10.28"}]}]
References
- package https://github.com/composer/composer
- web https://github.com/composer/composer/security/advisories/GHSA-f9f8-rm49-7jv2
- web https://github.com/FriendsOfPHP/security-advisories/blob/master/composer/composer/CVE-2026-45793.yaml
- web https://github.com/advisories/GHSA-f9f8-rm49-7jv2
- web https://github.com/composer/composer/commit/3f5e7f9fbfa541137d6d1d5643ec3b718e9d5039
- web https://github.com/composer/composer/commit/65e6390c49f1a11cd8b660d81822086db51fe2d1
- web https://github.com/composer/composer/commit/e66c8fdb7ff5409bd2f358c5f194038e49e93714
- web https://github.com/composer/composer/pull/12853
- web https://github.com/composer/composer/pull/12855
- web https://github.com/composer/composer/releases/tag/1.10.28
- web https://github.com/composer/composer/releases/tag/2.2.28
- web https://github.com/composer/composer/releases/tag/2.9.8
- web https://nvd.nist.gov/vuln/detail/CVE-2026-45793