Vulnerability details

CVE-2026-73418

@auth corenextauthjs next-auth

NextAuth.js: getToken() throws an uncaught exception on malformed Bearer authorization headers

CVSS 3.1
7.5High

Official description

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.

CVSS scores

ScoreVersionSourceVector
7.5High 3.1 CVEProject cvelistV5 (CNA) (GitHub_M) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

VendorProductVersionsSource
@auth core >= 0.1.0, < 0.41.3 CVEProject cvelistV5 (CNA)
nextauthjs next-auth >= 4.0.6, <= 4.24.14 CVEProject cvelistV5 (CNA)
nextauthjs next-auth >= 5.0.0-beta.0, <= 5.0.0-beta.31 CVEProject cvelistV5 (CNA)

References and advisories

7
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Details

Published
2026-08-12
Last updated
2026-08-13
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.87%
Probability of exploitation in 30 days
59.2%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
None
Technical impact
Partial

Weaknesses (CWE)

  • CWE-20
    Improper Input Validation
  • CWE-248
    Uncaught Exception