CVE-2026-55370
Logto: TOTP code can be replayed within the RFC 6238 validity window (one-time use violation)
- State
- Published
- Severity
- 6.4 Medium
- Published
- Jul 10, 2026
- Updated
- Jul 10, 2026
- Reserved
- Jun 16, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.4 Medium | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N | GitHub_M |
Weaknesses
- CWE-294 Authentication Bypass by Capture-replay
Affected Products
| Product | Versions |
|---|---|
logtologto-io |
|
References
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