Auth bypass in Umami
CVE-2026-121531
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Umami — versions 3.3.*, 3.4.0, 3.4.1
Weakness classification (CWE)
References
- vuldb.com/vuln/430290 (vdb-entry)
- vuldb.com/vuln/430290/cti (signature, permissions-required)
- vuldb.com/cve/CVE-2026-121531 (third-party-advisory)
- vuldb.com/submit/1019994 (third-party-advisory)
- github.com/waterhunter2000-svg/vulnerability-reports (related)
- github.com/umami-software/umami/security/advisories/GHSA-29fx-pxjg-35rm (broken-link)
- github.com/waterhunter2000-svg/vulnerability-reports/blob/main/03-umami-enforce… (exploit)
Frequently asked questions
- What is CVE-2026-121531?
- CVE-2026-121531 is a medium-severity vulnerability in Umami, classified under Improper Authentication. CVSS score: 6.3/10. Published 2026-11-03.
- How severe is CVE-2026-121531?
- Medium severity. CVSS v3 base score is 6.3 out of 10.