Improper input validation in @Auth Core
CVE-2026-73418
NextAuth.js provides authentication for Next.js. Prior to @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32, the exported getToken() helper in the next-auth/jwt and @auth/core/jwt modules 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 decodeURIComponent() to throw instead of treating the token as invalid. Because getToken() is commonly called in API routes, middleware, and server-side request handlers, a single unauthenticated request can trigger an unhandled exception in code paths that authenticate requests, causing a per-request denial of service without exposing tokens, sessions, or other data and without bypassing authentication. This issue is fixed in @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.009 (57.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 57.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.009 · change: +0.004
Affected products
- @Auth Core — versions >= 0.1.0, < 0.41.3
- Nextauthjs Next-Auth — versions >= 4.0.6, <= 4.24.14, >= 5.0.0-beta.0, <= 5.0.0-beta.31
Weakness classification (CWE)
References
- github.com/nextauthjs/next-auth/security/advisories/GHSA-xmf8-cvqr-rfgj
- github.com/nextauthjs/next-auth/pull/13469
- github.com/nextauthjs/next-auth/commit/5bca2399a79ba8d116ca5179b4b1ebcd152e7f05
- github.com/nextauthjs/next-auth/commit/e707770f00c52b3479e43422b0200b059149ed53
- github.com/nextauthjs/next-auth/releases/tag/@auth/core@0.41.3
- github.com/nextauthjs/next-auth/releases/tag/next-auth@4.24.15
- github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32
Frequently asked questions
- What is CVE-2026-73418?
- CVE-2026-73418 is a high-severity vulnerability in @Auth Core, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-08-12.
- How severe is CVE-2026-73418?
- High severity. CVSS v3 base score is 7.5 out of 10.