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CVE-2026-49473 high CVSS 8.8

Vulnerability in @cedar-policy/authorization-for-expressjs (CVE-2026-49473)

Summary

Vulnerability in @cedar-policy/authorization-for-expressjs (CVE-2026-49473). Successful exploitation can lead to full system takeover. Exploitable via GET /users. Mitigation: upgrade to 0.3.0 or later.

Original description

The description as published by the source.

Summary

@cedar-policy/authorization-for-expressjs is an open-source Express.js middleware that integrates Cedar authorization into Express applications by mapping HTTP requests to Cedar actions and evaluating authorization policies before allowing requests to proceed. An issue exists where, under certain circumstances, the middleware matches incoming requests against Cedar action mappings using req.originalUrl, which includes the query string, while Express routes requests using only the path component.

Impact

The middleware uses req.originalUrl to match incoming requests against Cedar action mappings. In Express, req.originalUrl includes the query string, while route matching uses only the path. This creates a divergence between what Cedar authorizes and what Express executes.

When an application defines separate actions for overlapping path prefixes with different authorization requirements (for example, GET /users for listing all users with admin-only access, and GET /users/{id} for retrieving a single user with any authenticated user access), an actor can append a query string to bypass the more restrictive policy. Sending GET /users/?x=1 causes the middleware to match against /users/{id} (with id parameter set to ?x=1) and evaluate the less restrictive action, while Express routes the request to the /users list handler. This allows inappropriate access to the more restrictive endpoint.

Impacted versions

<= 0.2.0

Patches

This issue has been addressed i…

Source: GitHub Security Advisories (Global) 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-2026-49473 has been found in @cedar-policy/authorization-for-expressjs.
Attackers can target a specific entry point like GET /users over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade @cedar-policy/authorization-for-expressjs to 0.3.0 or later.
If unsure, ask your IT team or search "@cedar-policy/authorization-for-expressjs CVE-2026-49473" on the vendor's site.

CVE-2026-49473 (@cedar-policy/authorization-for-expressjs) — CWE-436 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /users / GET /users/{id} / GET /users/
Patched: 0.3.0 — apply immediately
Workaround: Validate and sanitize incoming request paths before they reach the authorization middleware.
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-436) exists in @cedar-policy/authorization-for-expressjs. Attackers reach the vulnerable code path via GET /users.

📍 Affected scope

Check the vendor advisory for the affected versions of @cedar-policy/authorization-for-expressjs. Attack surface: GET /users / GET /users/{id} / GET /users/.

🔥 Severity

Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 0.3.0.

🛡️ Workaround

Workaround: Validate and sanitize incoming request paths before they reach the authorization middleware.

🔍 Detection

Search webserver/proxy logs for unusual GET /users requests with malformed payloads or SQL meta-characters. Run grep -r '@cedar-policy/authorization-for-expressjs' . 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

  1. 1
    Identify exposure identify 
    grep -r '@cedar-policy/authorization-for-expressjs' . | 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 @cedar-policy/authorization-for-expressjs を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'GET /users' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで GET /users への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply temporary workaround mitigate 
    Validate and sanitize incoming request paths before they reach the authorization middleware.

    パッチが適用されるまでの応急処置として、Validate and sanitize incoming request paths before they reach the authorization middleware. を実施。回避策の副作用 (機能低下) を確認した上で。

  4. 4
    Apply patch patch 
    Upgrade @cedar-policy/authorization-for-expressjs to 0.3.0

    ステージング環境で 0.3.0 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 2 で見つけた異常検知の続報チェックを含めること。

  5. 5
    Post-deployment verification verify 
    Replay attack against GET /users on staging to confirm patch closes the vector

    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 2 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

npm @cedar-policy/authorization-for-expressjs
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.3.0"}]}]

References

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