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CVE-2026-73418 high CVSS 7.5

Vulnerability in @auth/core (CVE-2026-73418)

Summary

Vulnerability in @auth/core (CVE-2026-73418). Risk of unauthorized operations or information disclosure. Exploitable via Authorization header. Mitigation: upgrade to 0.41.3 or later.

Original description

The description as published by the source.

Summary

The exported getToken() helper (next-auth/jwt and @auth/core/jwt) can throw an uncaught exception when it reads a malformed Authorization: Bearer … header. When no session cookie is present, getToken() URL-decodes the bearer value before validating it, and malformed percent-encoding causes the decode step to throw rather than being treated as an invalid token. Because getToken() is commonly called in API routes, middleware, and other request handlers, a single unauthenticated request can trigger an unhandled exception in code paths that authenticate requests.

Am I affected?

You are affected if all of the following hold:

  • You use next-auth <= 5.0.0-beta.25 (or @auth/core exposing the same getToken() implementation).
  • Your application calls getToken() directly — for example in a Route Handler, middleware, or server-side request handler.
  • You do not wrap that getToken() call in your own try/catch.

You are not affected if you only use the framework's auth() helper and never call getToken() yourself, or if every getToken() call site already has its own exception handling.

Impact

  • Denial of service: an unauthenticated request carrying a malformed Bearer authorization header can raise an unhandled exception in any handler that calls getToken().
  • The impact is per-request and limited to availability; it does not expose tokens, sessions, or other data, and does not bypass authentication.

CWE-20: Improper Input Val…

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-2026-73418 has been found in @auth/core.
Attackers can target a specific entry point like Authorization header over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade @auth/core to 0.41.3 or later.
If unsure, ask your IT team or search "@auth/core CVE-2026-73418" on the vendor's site.

CVE-2026-73418 (@auth/core) — CWE-20 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Authorization header / null / Authorization
Patched: 0.41.3 — 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-20) exists in @auth/core. Attackers reach the vulnerable code path via Authorization header without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of @auth/core. Attack surface: Authorization header / null / Authorization.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 0.41.3.

🛡️ 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 '@auth/core' . 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 '@auth/core' . | 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 @auth/core 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
    Apply patch patch 
    Upgrade @auth/core to 0.41.3

    ステージング環境で 0.41.3 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。

  3. 3
    Post-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

npm @auth/core
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.41.3"}]}]
npm next-auth
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.24.15"}]}]

References

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