CVE-2026-55370
Logto: TOTP code can be replayed within the RFC 6238 validity window (one-time use violation)
CVSS Score
6.4
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-294 |
| Vendor | logto-io |
| Product | logto |
| Published | Jul 10, 2026 |
| Last Updated | Jul 10, 2026 |
Stay Ahead of the Next One
Get instant alerts for logto-io logto
Be the first to know when new medium vulnerabilities affecting logto-io logto are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
logto-io / logto
< 1.41.0
References
github.com: https://github.com/logto-io/logto/security/advisories/GHSA-6wj7-c66m-6c82 github.com: https://github.com/logto-io/logto/pull/9109 github.com: https://github.com/logto-io/logto/commit/9118867f6cbadc7291cf913beb4fede91ed5d374 github.com: https://github.com/logto-io/logto/releases/tag/v1.41.0