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TI-2026-39950 Aliases CVE-2026-55370

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

Priority LOW 30CWE-294Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
High
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-294.

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 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00336 27th percentileScored 2026-11-07
Fix Fixed logto (logto-io): 1.41.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
logto-iologtobefore 1.41.01.41.0Patch availableCNA
  • logto Vendorlogto-io Affected before 1.41.0 Fixed in 1.41.0 Patch available CNA

Remediation

  • Fix · CNA logto (logto-io) Fixed in 1.41.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55370

References

Other 4

  • TI-2026-44494 Logto: ReDoS via unescaped user input in email subaddressing regex (blockSubaddressing) CVSS 3.1HIGH 7.5
  • TI-2026-40275 XML injection in logto-io logto CVSS 3.1HIGH 8.5
  • TI-2026-56728 Logto Server-Side Request Forgery via OIDC SSO Connector Issuer URL CVSS 4.0HIGH 8.2
  • TI-2026-39955 Logto: Account Center MFA management step-up bypass via WebAuthn registration verification CVSS 3.1HIGH 8.1
  • TI-2026-45089 Logto: Account API can disclose stored third-party provider tokens without the identities scope CVSS 3.1HIGH 7.6
  • TI-2026-45086 Logto: OS command injection vulnerability exists in the Commitlint workflow CVSS 3.1MEDIUM 6.3
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences