CVE-2026-107369: Improper Validation of Post-Login Redirect URL in nextjs-auth0

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-13 · updated 2026-10-15
Weakness: CWE-601

Description

The auth0/nextjs-auth0 SDK validates that the returnTo parameter is a same-origin URL. The SDK then stores this value and, in a later step, reconstructs it for the post-authentication redirect. The reconstruction logic can produce a URL that browsers interpret as an absolute or scheme-relative path, leading to a redirect to an unintended domain.

Affected products

auth0 nextjs-auth0: before 4.32.0 — fixed in 4.32.0

How to fix

Upgrade to a fixed version: auth0 nextjs-auth0 4.32.0. Check the vendor advisory for mitigations.

References

https://github.com/auth0/nextjs-auth0/security/advisories/GHSA-5vvp-h2v6-59j6
https://trust.okta.com/security-advisories/improper-validation-of-post-login-redirect-url-in-nextjs-auth0-cve-2026-107369

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