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CVE-2026-40476
high
CVSS 7.5
Vulnerability in webonyx/graphql-php (CVE-2026-40476)
Summary
vulnerability in webonyx/graphql-php (CVE-2026-40476). Risk of unauthorized operations or information disclosure. Exploitable via ``OverlappingFieldsCanBeMerged``. Mitigation: upgrade to `15.31.5` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-40476** has been found in webonyx/graphql-php.
Attackers can target a specific entry point like ``OverlappingFieldsCanBeMerged`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade webonyx/graphql-php to **15.31.5** or later.
If unsure, ask your IT team or search "webonyx/graphql-php CVE-2026-40476" on the vendor's site.
CVE-2026-40476 (webonyx/graphql-php) — CWE-407 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: `OverlappingFieldsCanBeMerged`
Patched: `15.31.5` — 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
**A vulnerability** (CWE-407) exists in webonyx/graphql-php. Attackers reach the vulnerable code path via ``OverlappingFieldsCanBeMerged`` without authentication.
📍 Affected scope
webonyx/graphql-php — . Attack surface: `OverlappingFieldsCanBeMerged`.
🔥 Severity
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **15.31.5**.
🛡️ 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 'webonyx/graphql-php' .` 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 'webonyx/graphql-php' . | 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 `webonyx/graphql-php` 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 webonyx/graphql-php to 15.31.5ステージング環境で 15.31.5 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
webonyx/graphql-php
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"15.31.5"}]}]
Packagist
webonyx/graphql-php
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"15.31.5"}]}]
References
- advisory https://nvd.nist.gov/vuln/detail/CVE-2026-40476
- package https://github.com/webonyx/graphql-php
- web https://github.com/webonyx/graphql-php/releases/tag/v15.31.5
- web https://github.com/webonyx/graphql-php/security/advisories/GHSA-68jq-c3rv-pcrr
- web https://github.com/advisories/GHSA-68jq-c3rv-pcrr