Vulnerability in @auth/core (CVE-2026-73419)
Summary
Vulnerability in @auth/core (CVE-2026-73419). Confidential information can be exposed externally. Exploitable via state. Mitigation: upgrade to 0.41.3 or later.
Original description
The description as published by the source.
Summary
Auth.js stores the OAuth/OIDC anti-CSRF checks (state, nonce, and the PKCE verifier) in global cookies that are not bound to the provider that created them. On callback, a check value minted during a sign-in started with one provider can satisfy the callback for a different provider, because the stored cookie is not verified against the callback provider's identity (provider id, issuer, client id, or redirect URI). In a multi-provider app that allows account linking while logged in, this provider-confusion / mix-up condition can let an attacker link their account at a second provider to a victim's user.
Am I affected?
You may be affected if all of the following hold:
- You use
next-auth<= 4.24.14or>= 5.0.0-beta.1, <= 5.0.0-beta.31, or@auth/core<= 0.41.2. - You configure multiple OAuth/OIDC providers.
- You allow users to link additional providers while logged in.
- At least one configured provider's authorization request is observable by an attacker, and at least one target provider's callback can be satisfied without a PKCE verifier (i.e. it relies only on
stateor only onnonce).
You are not affected if you use a single OAuth provider, do not allow logged-in account linking, or all providers enforce PKCE.
Impact
- Account-linking confusion: an attacker can get their account at a target provider linked to the victim's Auth.js user, granting the attacker persistent sign-in to the victim's account through that linked provi…
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-2026-73419 has been found in @auth/core.
Attackers can target a specific entry point like state over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.8/10.
What to do: upgrade @auth/core to 0.41.3 or later.
If unsure, ask your IT team or search "@auth/core CVE-2026-73419" on the vendor's site.
CVE-2026-73419 (@auth/core) — CWE-345 / CVSS v3 6.8
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: state / nonce / events.linkAccount
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.
A vulnerability (CWE-345) exists in @auth/core. Attackers reach the vulnerable code path via state without authentication.
Check the vendor advisory for the affected versions of @auth/core. Attack surface: state / nonce / events.linkAccount.
Severity: Medium (CVSS 6.8/10). Confidential information can be exposed externally.
Update to 0.41.3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
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
-
1Identify 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。 -
2Apply 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。
-
3Post-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。