---
id: CVE-2026-55370
title: 'Logto is the modern, open-source auth infrastructure for SaaS and AI apps'
summary: >-
  Logto is the modern, open-source auth infrastructure for SaaS and AI apps.
  Prior to 1.41.0, Logto's existing TOTP verification accepted a successfully
  used TOTP code again while the code remained inside the RFC 6238 acceptance
  window bec…
severity: medium
cvss: 6.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N'
cwe:
  - CWE-294
published: '2026-07-10'
updated: '2026-07-10'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55370'
references:
  - url: >-
      https://github.com/logto-io/logto/commit/9118867f6cbadc7291cf913beb4fede91ed5d374
    label: security-advisories@github.com
  - url: 'https://github.com/logto-io/logto/pull/9109'
    label: security-advisories@github.com
  - url: 'https://github.com/logto-io/logto/releases/tag/v1.41.0'
    label: security-advisories@github.com
  - url: 'https://github.com/logto-io/logto/security/advisories/GHSA-6wj7-c66m-6c82'
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00336
epssPercentile: 0.24174
ingestedAt: '2026-07-11T20:15:26.528Z'
---

## Overview

Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 1.41.0, Logto's existing TOTP verification accepted a successfully used TOTP code again while the code remained inside the RFC 6238 acceptance window because the verifier used otplib's stateless check with window = 1 and did not persist or compare the accepted TOTP time-step counter. An attacker who has the victim's first factor and captures a live TOTP value can replay that value to satisfy MFA during the same acceptance window. This issue is fixed in version 1.41.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.