CVE-2026-121531

Deferred Deferred - Pending Action

Umami Authentication Bypass via 2FA Policy Handler

Publication date: 2026-11-03

Last updated on: 2026-11-03

Assigner: VulDB

Description

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.

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Meta Information

Published

2026-11-03

Last Modified

2026-11-03

Generated

2026-11-04

AI Q&A

2026-11-04

EPSS Evaluated

N/A

NVD

CVE-2026-121531

Affected Vendors & Products

Vendor	Product	Version / Range
n/a	Umami	3.3.*
n/a	Umami	3.4.0
n/a	Umami	3.4.1

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-287	When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
CWE-308	The product uses an authentication algorithm that uses a single factor (e.g., a password) in a security context that should require more than one factor.

Attack-Flow Graph

Executive Summary

This vulnerability affects Umami versions 3.3.x, 3.4.0, and 3.4.1. It is located in the 2FA Policy Handler component, specifically in the file src/app/api/auth/login/route.ts. The issue allows attackers to bypass multi-factor authentication by manipulating the login process, reducing it to single-factor authentication.

Detection Guidance

This vulnerability affects Umami versions 3.3.x, 3.4.0, and 3.4.1 in the 2FA Policy Handler component. To detect it, check if your Umami instance is running one of these versions and inspect the file src/app/api/auth/login/route.ts for improper 2FA enforcement. No specific commands are provided in the context.

Impact Analysis

If exploited, this vulnerability could allow unauthorized remote attackers to gain access to user accounts with only single-factor authentication, bypassing intended security measures. This increases the risk of account compromise and potential data breaches.

Mitigation Strategies

Immediately upgrade Umami to a patched version if available. If no patch exists, disable single-factor authentication or enforce strict 2FA policies. Monitor login attempts for suspicious activity and restrict access to the login endpoint.

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