VYPR
Unrated severityNVD Advisory· Published Jul 10, 2026· Updated Jul 10, 2026

Logto: TOTP code can be replayed within the RFC 6238 validity window (one-time use violation)

CVE-2026-55370

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.

Affected products

1

Patches

Vulnerability mechanics

References

4

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