Vulnerability Description
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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/logto-io/logto/commit/9118867f6cbadc7291cf913beb4fede91ed5d37
- https://github.com/logto-io/logto/pull/9109
- https://github.com/logto-io/logto/releases/tag/v1.41.0
- https://github.com/logto-io/logto/security/advisories/GHSA-6wj7-c66m-6c82
FAQ
What is CVE-2026-55370?
CVE-2026-55370 is a vulnerability with a CVSS score of 6.4 (MEDIUM). 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 insi...
How severe is CVE-2026-55370?
CVE-2026-55370 has been rated MEDIUM with a CVSS base score of 6.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-55370?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.