CVE-2026-73421
NextAuth.js auth() can fail open on server misconfiguration, granting unauthenticated access.
Is CVE-2026-73421 being exploited?
Not confirmed. CVE-2026-73421 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.46% probability of exploitation in the next 30 days.
How severe is CVE-2026-73421?
CVE-2026-73421 is rated Critical. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-73421?
Yes. A fix has been recorded for CVE-2026-73421. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-73421 affect?
CVE-2026-73421 affects NextAuth.js (next-auth) <5.0.0-beta.32, Next.js apps using next-auth auth() in middleware/route handlers/RSC. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-73421?
Upgrade next-auth to >=5.0.0-beta.32 and verify AUTH_SECRET and provider endpoint configs.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authentication bypass: unauthenticated users can access routes protected only by session existence when server auth config errors occur.
Immediate action required
- affected>= 5.0.0-beta.4 and < 5.0.0-beta.32
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.