CVE-2026-121531 PUBLISHED

A vulnerability has been found in Umami 3.3.x/3.4.0/3.4.1. This affects an unknown part of the file src/app/api/auth/login/route.ts of the component 2FA Policy Handler. The manipulation leads to use of single-factor authentication. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

• waterhunter (VulDB User) reporter
• VulDB CNA Team coordinator

• VDB-430290 | Umami 2FA Policy route.ts single-factor authentication
• VDB-430290 | CTI Indicators (IOB, IOC, TTP, IOA)
• CVE-2026-121531 | CVE Analysis and Report
• Submit #1019994 | umami-software umami 3.4.0 Improper Authentication
• https://github.com/waterhunter2000-svg/vulnerability-reports
• https://github.com/umami-software/umami/security/advisories/GHSA-29fx-pxjg-35rm
• https://github.com/waterhunter2000-svg/vulnerability-reports/blob/main/03-umami-enforced-2fa-not-applied.md

• Use of Single-factor Authentication CWE
• Improper Authentication CWE