Incorrect Behavior Order: Validate Before Canonicalize in next-auth - CVE-2026-73420
Published: July 21, 2026 / Updated: August 16, 2026
Vulnerability identifier: #VU138941
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73420
CWE-ID: CWE-180
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to default email-address normalizer validates the address before applying Unicode normalization. A remote attacker can gain access to the target system.
Affected software
next-auth
How to mitigate CVE-2026-73420
Install updates from vendor's website.
next-auth - addressed in versions 4.24.15, 5.0.0 beta.32